What Are Sacred Scripture and Sacred Tradition? The Two Modes by Which Divine Revelation Is Transmitted
Short Answer
Sacred Scripture and Sacred Tradition are the two modes by which the revelation given by God through Jesus Christ and entrusted to the Apostles has been transmitted to the Church.
They are not two unrelated revelations, as though one set of doctrines came from the Bible and an entirely separate set came from oral folklore. There is one divine revelation, one Gospel, one apostolic deposit of faith, and ultimately one divine Author. Part of that revelation was committed to inspired writing; other teaching was transmitted by the Apostles through preaching, worship, ecclesiastical practice and the instruction of their successors.
St Paul therefore commanded Christians:
“Therefore, brethren, stand fast; and hold the traditions which you have learned, whether by word, or by our epistle.” 2 Thessalonians 2:14
The Council of Trent (1545–1563) expressed the same doctrine with particular precision. It taught that the Gospel is the “fountain” of saving truth, and that this truth is transmitted in “written books and unwritten traditions” received by the Apostles either from Christ Himself or through the inspiration of the Holy Ghost.
Thus the Catholic principle is not:
Revelation = Bible + a separate body of later Catholic inventions.
It is:
One revelation from God → entrusted to the Apostles → transmitted through Sacred Scripture and Apostolic Tradition → preserved and authentically taught by the Church.
That distinction is essential for understanding Christianity as it was actually transmitted from the Apostles.
Why This Question Matters
The disagreement over Scripture and Tradition lies close to the heart of the division between Catholicism and Protestantism.
Most Protestants accept Scripture as the uniquely infallible written Word of God, but many maintain that Scripture is the sole infallible rule of faith. Church tradition, councils and Fathers may be useful witnesses, but they remain subordinate and corrigible.
Catholicism makes a different claim. It certainly teaches the divine inspiration and supreme authority of Sacred Scripture. But it also teaches that Christ did not command His Apostles merely to write a book. He commanded them to teach, preach, baptise, govern, celebrate the sacred mysteries and hand on what they themselves had received.
The New Testament itself emerged from within this apostolic Church. Indeed, before all twenty-seven books of the New Testament had been written, Christians were already believing the Gospel, being baptised, celebrating the Eucharist, receiving episcopal and priestly ministry and living under apostolic authority.
The question therefore is not whether Scripture is the Word of God. It is. The deeper question is:
Did God intend all revealed Christian doctrine to be known exclusively from written texts, or did the Apostles also transmit authoritative teaching orally and through the life of the Church?
Both Scripture itself and the earliest Christian evidence point to the latter.
What the Catholic Church Teaches
There Is One Deposit of Divine Revelation
The safest starting point is to avoid speaking carelessly of Scripture and Tradition as though they were two independent revelations. At the Council of Trent, Session IV (8 April 1546), the Church described the Gospel preached by Christ and His Apostles as the source of Christian saving truth and moral discipline. It then taught that this revelation is preserved:
in inspired written books; and
in unwritten traditions received by the Apostles from Christ or transmitted by the Apostles under the inspiration of the Holy Ghost.
The Council declared that the Church receives and venerates both. Council of Trent, Session IV — Decree Concerning the Canonical Scriptures
This is important. Trent begins not with two separate fountains, but with the Gospel of Christ as the fountain of saving truth.
The distinction concerns the mode by which the apostolic revelation reaches us.
The First Vatican Council (1869–1870) repeated Trent's formulation in the dogmatic constitution Dei Filius, chapter 2. Supernatural revelation, it taught, is contained in the written books and unwritten traditions received from Christ by the Apostles or transmitted by the Apostles under the Holy Ghost and handed down to the Church. First Vatican Council, Dei Filius, Chapter 2 — On Revelation
There is therefore one revelation, but more than one mode by which that revelation was transmitted.
What Is Sacred Scripture?
Sacred Scripture is the written Word of God contained in the canonical books of the Old and New Testaments, written under the inspiration of the Holy Ghost.
The human authors truly wrote, using their own faculties and styles, yet God is the principal Author of Scripture. St Paul writes:
“All scripture, inspired of God, is profitable to teach, to reprove, to correct, to instruct in justice.” 2 Timothy 3:16–17
The Catholic Church therefore does not place Scripture beneath Tradition. Scripture possesses the unique character of divine inspiration. Sacred Tradition, by contrast, is not another collection of inspired books.
What Is Sacred Tradition?
In the strict doctrinal sense,
Sacred Tradition is the transmission of revealed teaching received from Christ and the Apostles which was not committed to inspired writing by its original apostolic transmitters but was handed down within the Church.
The word “unwritten” can therefore be misunderstood. It does not mean that a tradition may never subsequently have been written down. For example, an Apostolic Tradition might originally have been taught orally and practised throughout the churches. A Father of the Church might then describe it in writing two centuries later. It remains an unwritten Apostolic Tradition in the technical sense because it was not transmitted to the Church as part of an inspired canonical book.
St Robert Bellarmine (1542–1621), Doctor of the Church, makes this distinction in De Verbo Dei, Book IV. He distinguishes traditions deriving from Christ, apostolic traditions instituted by the Apostles under the Holy Ghost, and later ecclesiastical traditions established by Church authority.
That last category is particularly important.
Not everything called a “tradition” is Sacred Tradition.
A Catholic devotional custom, vestment style, fasting regulation, liturgical discipline or local practice may be ancient and venerable without forming part of divinely revealed Apostolic Tradition.
Scripture Itself Teaches Oral Apostolic Tradition
The strongest initial evidence for Sacred Tradition is found within Scripture itself.
“By Word, or by Our Epistle”
St Paul's command to the Thessalonians could hardly be more explicit:
“Hold the traditions which you have learned, whether by word, or by our epistle.” 2 Thessalonians 2:14
Paul identifies two forms in which the same apostolic teaching had reached the Thessalonians:
by word and by epistle.
He does not tell them to retain the written teaching while allowing the oral teaching to disappear. He commands them to hold both.
Paul Commands Oral Transmission to Continue
The principle becomes even clearer in St Paul's instruction to Timothy:
“The things which thou hast heard of me by many witnesses, the same commend to faithful men, who shall be fit to teach others also.” 2 Timothy 2:2
Notice the sequence:
Paul → Timothy → faithful men → others.
This is deliberate intergenerational transmission of apostolic teaching. Nothing in the passage says that Timothy should transmit only what Paul had already written in his epistles. Paul explicitly speaks about things Timothy had heard.
The Corinthians Were Expected to Preserve What Paul Delivered
Paul similarly praises the Corinthians for retaining what he had handed down:
“I praise you, brethren, that in all things you are mindful of me: and keep my ordinances as I have delivered them to you.” 1 Corinthians 11:2
The Christian faith was therefore something delivered, received and preserved within the apostolic communities.
Not Everything Christ Did Was Written
St John concludes his Gospel:
“But there are also many other things which Jesus did; which, if they were written every one, the world itself, I think, would not be able to contain the books that should be written.” John 21:25
This verse by itself does not prove any particular Catholic Tradition. It would be an overstatement to use it that way. It does, however, disprove the assumption that everything Christ said and did necessarily had to be recorded in the canonical Gospels.
The Early Church Fathers
The earliest Christians did not behave as though Christian doctrine consisted solely of propositions recoverable independently from a completed New Testament. They repeatedly appealed to the faith handed down through the Apostles and their successors.
St Irenaeus of Lyons
St Irenaeus of Lyons (c. AD 130–202), writing Against Heresies around AD 180, appealed directly to apostolic succession and Tradition against the Gnostics. In Book III, chapter 4, he makes a remarkable argument: even if the Apostles had left Christians no written Scriptures, believers would still have had to follow the Tradition entrusted by the Apostles to the churches. St Irenaeus, Against Heresies, III.4.1
This is only about a century and a half after the Crucifixion. Irenaeus's conception of Christianity is therefore neither:
Bible versus Tradition nor private oral legends added to Scripture.
Rather, the Apostles preached the Gospel, transmitted it to churches, appointed successors and also left inspired writings.
St Basil the Great
An exceptionally explicit testimony comes from St Basil the Great (AD 329–379) in On the Holy Spirit, written about AD 375.
In chapter 27, section 66, Basil distinguishes teachings received in writing from those received through Apostolic Tradition. He says that some ecclesiastical beliefs and practices come from written teaching while others were received from the Tradition of the Apostles and that both possess authority in Christian life. St Basil the Great, On the Holy Spirit, Chapter 27, §66
Basil then gives examples, including:
making the Sign of the Cross;
praying towards the east;
certain prayers surrounding the Eucharistic consecration;
the blessing of baptismal water and oil;
baptismal renunciations;
triple immersion at baptism.
This evidence is extremely important, but it should be used carefully. Basil is demonstrating that unwritten apostolic transmission was an accepted principle of fourth-century Christianity.
He is not thereby establishing that every disciplinary detail in his list is itself an immutable dogma. Some traditions concern revealed doctrine; others concern the ancient liturgical and disciplinary expression of that doctrine.
Tertullian
A still earlier witness appears in Tertullian (c. AD 155–220) in De Corona (On the Crown), written around AD 211.
Tertullian lists Christian practices for which no explicit Scriptural command could be cited, including the Sign of the Cross, baptismal customs, offerings for the dead and certain practices surrounding Sunday worship. He explains these practices by appeal to inherited Christian Tradition. Tertullian, On the Crown, Chapters 3–4
Tertullian should be treated here as an important early Christian historical witness, not as though every statement in his writings constituted authoritative Catholic doctrine. His later association with Montanism also requires historical care.
Nevertheless, his testimony shows that Christians at the beginning of the third century already understood that authentic ecclesiastical practice was not limited to what could be supported by an explicit biblical command.
How Can We Know That a Tradition Is Apostolic?
This raises an obvious question. Someone could claim almost anything and call it “tradition.”
Catholicism does not teach that every old custom, local legend or popular devotion constitutes Apostolic Tradition. Several signs were traditionally used to identify apostolic origin.
Universality
A teaching or practice found throughout geographically separated churches from very early times is difficult to explain as a late local invention.
Antiquity
The closer a practice can be traced to the apostolic age, the stronger the historical evidence for its primitive origin.
Continuity
A doctrine consistently transmitted through successive generations of bishops, Fathers, councils, liturgies and catechetical instruction carries a fundamentally different evidentiary weight from a practice suddenly appearing centuries later.
Agreement With the Received Faith
Authentic Apostolic Tradition cannot contradict Sacred Scripture because Scripture and genuine Tradition ultimately have the same divine source.
The Judgment of the Church
Ultimately the individual Christian is not required to reconstruct Christianity independently from surviving historical documents. St Paul calls the Church:
“the church of the living God, the pillar and ground of the truth.” 1 Timothy 3:15
The Church received the apostolic deposit corporately and possesses the authority to guard, teach and distinguish authentic Apostolic Tradition from merely human customs.
Examples of Sacred and Apostolic Tradition
Several examples help make the principle concrete.
1. The Canon of the New Testament
Perhaps the most immediately understandable example is the canon of Scripture itself.
The Bible does not contain an inspired table of contents identifying:
Matthew as inspired;
Mark as inspired;
Luke as inspired;
John as inspired;
Hebrews as inspired;
Revelation as inspired;
while excluding every other early Christian writing.
The Church had to receive, preserve and distinguish the apostolic writings.
By the fourth century, St Athanasius of Alexandria (c. AD 296–373) gave, in his Thirty-Ninth Festal Letter (AD 367), the earliest surviving list containing precisely the twenty-seven books now recognised as the New Testament. St Athanasius, Festal Letter 39, AD 367
This does not mean Athanasius personally created the canon. He was witnessing to a process of ecclesiastical reception already underway. The principle is important:
Before one can appeal to “the Bible alone,” one must first know which books constitute the Bible.
That knowledge itself reaches the Christian through the historical and teaching Tradition of the Church.
St Augustine of Hippo (AD 354–430), writing in AD 397, expressed the close connection between Gospel and Church when he wrote in Against the Fundamental Epistle of Manichaeus, chapter 5:
“I should not believe the gospel except as moved by the authority of the Catholic Church.” St Augustine, Against the Fundamental Epistle of Manichaeus, 5.6
Augustine is not saying that the Church makes an uninspired book inspired. God is the Author of Scripture. He is explaining the epistemological point:
how does the believer reliably know which writings possess apostolic and divine authority?
The testimony and authority of the Church are indispensable.
2. Infant Baptism
Infant baptism provides another important example. There is no New Testament verse saying in those exact words:
“The Apostles commanded that infants must be baptised.”
Yet infant baptism appears extremely early in Christian history and was regarded by important ancient witnesses as inherited from the Apostles.
Origen of Alexandria (c. AD 185–253/254), in his Commentary on Romans, states that the Church received from the Apostles the tradition of baptising infants. There is a textual qualification worth mentioning: the relevant portion survives through the later Latin translation and adaptation of Rufinus rather than in Origen's original Greek. The passage is therefore valuable evidence but should not be treated as though the exact surviving wording can certainly be attributed word-for-word to Origen.
Even more significantly, St Augustine, arguing against the Donatists around AD 400, states a broader principle: practices universally held throughout the Church, which were not instituted by councils yet had been continuously observed, were rightly considered to have come down from apostolic authority. St Augustine, On Baptism, Against the Donatists, Book IV, Chapter 24
This demonstrates how the ancient Church reasoned about Apostolic Tradition. A universal practice did not require the discovery of a lost apostolic manuscript before it could reasonably be regarded as apostolic.
3. Sunday as the Principal Day of Christian Worship
Christians worship on Sunday rather than continuing the Jewish Sabbath as the principal day of Christian liturgical assembly. This practice certainly has Scriptural foundations: Christ rose on the first day of the week, and the New Testament contains evidence of Christian gathering on that day. But the precise ecclesiastical observance was also transmitted through apostolic practice.
The Roman Catechism, promulgated following the Council of Trent, states in its explanation of the Third Commandment that the Apostles consecrated the first day of the week to divine worship and called it the Lord's Day. Roman Catechism — The Third Commandment
The Didache, an ancient Christian work generally dated to the late first or early second century, commands Christians to assemble on the Lord's Day, break bread and give thanks. Didache, Chapter 14
Similarly, St Justin Martyr (c. AD 100–165), in his First Apology around AD 155, describes Christians assembling on Sunday for readings, prayer and the Eucharist. St Justin Martyr, First Apology, Chapter 67
Here Scripture and Tradition do not compete. They mutually illuminate the apostolic Christian practice.
4. The Sign of the Cross
Christians have made the Sign of the Cross from very early centuries. There is no Scriptural command reading:
“Before beginning ordinary actions, trace the Sign of the Cross upon yourself.”
Nevertheless, Tertullian around AD 211 describes Christians marking themselves with the Cross repeatedly in ordinary life. More than a century and a half later, St Basil explicitly includes the Sign of the Cross among practices received through unwritten Tradition. This is a good example of why distinctions are necessary.
The Sign of the Cross is an ancient apostolic ecclesiastical tradition expressing revealed truths concerning the Trinity, the Incarnation and Redemption. But the precise gesture itself is not a separate dogma equal to, for example, the divinity of Christ.
5. Ancient Baptismal and Liturgical Practices
St Basil's list includes other practices surrounding baptism, Eucharistic worship, anointing, the direction of prayer and liturgical formulae. These examples establish something historically significant:
The fourth-century Church did not believe that every legitimate element of Christian worship had to be justified by an explicit verse of Scripture.
Christians understood themselves as heirs of a living apostolic inheritance.
Some elements transmitted through that inheritance expressed revealed doctrine.
Others were apostolic ecclesiastical practices.
Still others could eventually develop or change without any change to the revealed Faith.
That distinction prevents the careless conclusion that “if it is traditional, it must be divinely revealed.”
Sacred Tradition, Apostolic Tradition and Ecclesiastical Tradition
The terminology becomes clearer if we distinguish three categories traditionally discussed by Catholic theologians.
| Type | Meaning | Example |
|---|---|---|
| Divine Tradition | Revelation given by Christ to the Apostles and transmitted by them. | Teachings received directly from Christ but not necessarily recorded explicitly in inspired Scripture. |
| Apostolic Tradition | Teaching or practice established and transmitted by the Apostles under the Holy Ghost. | Certain sacramental, liturgical and ecclesiastical practices. |
| Ecclesiastical Tradition | Laws, disciplines or customs instituted later by legitimate Church authority. | Particular fasting disciplines, liturgical regulations or ecclesiastical customs. |
St Robert Bellarmine discusses these distinctions in De Verbo Dei, Book IV.
The first two categories may participate directly in the apostolic deposit, depending upon their subject. The third does not constitute new divine revelation. This distinction also explains why Church discipline can sometimes change while dogma cannot.
Scripture, Tradition and the Teaching Church
There is one further distinction to make. The Magisterium, or teaching authority of the Church, should not be imagined as a third reservoir of revelation alongside Scripture and Tradition. The Church does not possess authority to invent new revelation.
Rather:
Sacred Scripture and Sacred Tradition contain and transmit the apostolic deposit.
The Magisterium guards, explains and authoritatively proposes that deposit.
The Roman Catechism describes Christian doctrine as derived from the Word of God, embracing both Scripture and Tradition. Roman Catechism — Preface
The relationship can therefore be represented simply:
Christ → Apostles → one deposit of faith
which is transmitted through:
Sacred Scripture + Sacred Tradition
and preserved and taught by:
the Church's divinely established teaching authority.
The Main Objection: “Shouldn't Christians Follow the Bible Alone?”
The strongest Protestant objection is not normally that history or the Fathers are useless. Rather, the classical Protestant position is that Scripture alone is the only infallible rule by which every later ecclesiastical tradition must ultimately be judged.
Human memory can fail. Customs can develop. Churches can become corrupt. Scripture, being inspired by God, therefore provides a fixed and certain standard. That objection identifies a genuine danger: merely human tradition can indeed become corrupt.
Christ Himself condemned traditions of men when they displaced the commandment of God. Matthew 15:3–9
Catholicism does not teach otherwise.
The question, however, is whether Apostolic Tradition itself belongs in that category. St Paul plainly distinguishes authoritative traditions received from the Apostles from corrupt human traditions. He commands Christians to hold apostolic traditions whether transmitted orally or in writing. Consequently, the biblical opposition is not:
Scripture versus Tradition.
It is:
divine and apostolic teaching versus merely human teaching that contradicts God.
“Doesn't 2 Timothy 3:16–17 Teach Scripture Alone?”
Another common argument appeals to St Paul's statement:
“All scripture, inspired of God, is profitable to teach…”
and that through it the man of God may be “perfect, furnished to every good work.” 2 Timothy 3:16–17
Catholics affirm every word of this passage. The question is whether profitable and sufficient for equipping means the exclusive rule from which all Christian doctrine must be derived.
Paul does not say that. Indeed, in the very same epistle, Paul instructs Timothy to transmit orally to faithful men what Timothy had heard from Paul. 2 Timothy 2:2
And elsewhere Paul commands Christians to retain traditions received both orally and in writing. 2 Thessalonians 2:14
It would therefore be difficult to interpret Paul as simultaneously commanding oral Apostolic Tradition while teaching that only written apostolic teaching possesses binding authority.
“Couldn't Oral Tradition Have Become Corrupted?”
If Sacred Tradition meant an uncontrolled chain of private recollections passed from individual to individual for centuries, this objection would be formidable. But that is not the Catholic claim.
Apostolic Tradition was transmitted publicly within a visible Church through:
episcopal succession;
preaching;
creeds;
baptismal profession;
Eucharistic worship;
catechesis;
councils;
liturgical practice;
sacramental discipline;
churches founded by the Apostles;
continuing communion among those churches.
This is precisely the type of argument St Irenaeus employed against the Gnostics. The Gnostics claimed possession of secret teachings.
Irenaeus answered by pointing to the publicly identifiable churches founded by the Apostles and the succession of their bishops. Authentic Catholic Tradition is therefore almost the opposite of a secret rumour. It is the public inheritance of the Apostolic Church.
Does Every Catholic Doctrine Have to Be Completely Absent From Scripture Before It Counts as Tradition?
No. This is another important misconception. Scripture and Tradition substantially overlap. The Trinity, divinity of Christ, Resurrection, baptism, Eucharist and many other doctrines are strongly attested in Scripture and were simultaneously transmitted through preaching, creed, liturgy and ecclesiastical teaching. Tradition is not merely a container for doctrines that cannot be found anywhere in the Bible.
Rather, Tradition also:
preserves the authentic understanding of Scripture;
identifies its canonical books;
preserves apostolic interpretation;
supplies historical context;
records apostolic worship and practice;
protects doctrines against interpretations foreign to the faith in which Scripture was originally received.
Thus Scripture and Tradition are distinct but inseparable witnesses to the same apostolic revelation.
What We Can and Cannot Conclude
Established Catholic doctrine: Divine revelation was entrusted to the Apostles and is transmitted to the Church through inspired Sacred Scripture and authentic unwritten Apostolic Tradition. The Council of Trent and First Vatican Council expressly teach the authority of both.
Established Catholic doctrine: Sacred Scripture is divinely inspired. Sacred Tradition must not be understood as another set of inspired books or as a rival revelation.
Established Catholic doctrine: Authentic Apostolic Tradition cannot contradict Sacred Scripture. The same God is ultimately the source of both.
Certain and common Catholic teaching: The Church's Magisterium does not constitute a new revelation. Its function is to preserve, interpret and authoritatively teach the apostolic deposit.
Established historical fact: Early Christian writers such as Irenaeus, Tertullian, Basil and Augustine explicitly appealed to ecclesiastical and apostolic traditions that were not derived merely from explicit Scriptural commands.
Established historical fact: Ancient Christian worship already included practices—such as Sunday Eucharistic assembly and various baptismal customs—which were transmitted through the life of the Church as well as reflected in written sources.
Strong theological conclusion: The proposition that the Apostles intended written Scripture to be the only binding mode of transmitting revelation is difficult to reconcile with St Paul's explicit command to retain teaching transmitted both “by word” and “by epistle.”
Disputed theological question: Catholic theologians have discussed whether all revealed doctrine is at least implicitly contained in Scripture—sometimes called the question of Scripture's “material sufficiency”—or whether some revealed truths are known from Tradition without even implicit Scriptural inclusion. The Church's definitions concerning Scripture and Tradition should not be stretched unnecessarily into resolving every later theological formulation of this question.
What is defined is sufficient for the present argument:
not all apostolic authority is reduced to an exclusively written rule of faith.
What cannot be concluded: One cannot take any old Catholic custom and simply label it “Apostolic Tradition.”
What cannot be concluded: The existence of Sacred Tradition does not make every disciplinary law, private revelation, popular devotion or theological opinion an article of faith.
What is not necessary to establish the argument: It is unnecessary to produce an unbroken written quotation from every generation proving every apostolic practice. The very concept of unwritten Tradition means that its transmission may occur through the Church's continuous teaching, worship and practice before eventually appearing explicitly in surviving written sources.
Conclusion
Sacred Scripture and Sacred Tradition are not competing authorities derived from separate revelations. They are the two principal modes by which one apostolic revelation reaches the Church.
Christ taught the Apostles. The Apostles preached, instructed, governed, celebrated the sacred mysteries and established churches. Some of their teaching was committed to inspired writing. Other teaching and practice was handed down within the Church. St Paul himself therefore speaks naturally of apostolic teaching transmitted both:
“by word” and “by our epistle.”
The earliest Christians understood the Faith in precisely this way. St Irenaeus appealed to the Tradition preserved in apostolic churches. Tertullian recorded unwritten Christian practices. St Basil explicitly distinguished written teaching from apostolic traditions received without writing. St Augustine regarded universal practices not traceable to later councils as evidence of apostolic origin.
The Catholic position is therefore not that Scripture is incomplete or defective. Sacred Scripture is divinely inspired and wholly true. Rather, the mistake lies in assuming that Christ intended Christianity itself to be reducible to a book interpreted apart from the living Apostolic Church from which that book was received.
The Catholic principle is more ancient:
one Lord, one Gospel, one apostolic Faith—transmitted in Sacred Scripture and Sacred Tradition, preserved in the Church founded by Jesus Christ.
Primary Sources
Sacred Scripture
2 Thessalonians 2:14 — apostolic traditions transmitted “by word” and “by epistle.”
2 Timothy 2:2 — oral apostolic teaching transmitted through successive teachers.
1 Corinthians 11:2 — preservation of what Paul delivered.
1 Timothy 3:15 — the Church as “pillar and ground of the truth.”
2 Timothy 3:16–17 — divine inspiration and utility of Scripture.
Matthew 15:3–9 — condemnation of merely human tradition contrary to God's commandments.
John 21:25 — not everything Christ did was committed to writing.
Council of Trent (1545–1563), Session IV, Decree Concerning the Canonical Scriptures, 8 April 1546.
Council of Trent, Session IV
First Vatican Council (1869–1870), Dei Filius, Dogmatic Constitution on the Catholic Faith, 24 April 1870, chapter 2, “On Revelation.”
Dei Filius, Chapter 2
Catechism of the Council of Trent, Preface.
Roman Catechism — Preface
Catechism of the Council of Trent, Part III, Third Commandment.
Roman Catechism — The Third Commandment
St Irenaeus of Lyons (c. AD 130–202), Against Heresies (c. AD 180), III.4.1.
Against Heresies, III.4.1
Tertullian (c. AD 155–220), On the Crown (De Corona, c. AD 211), chapters 3–4.
On the Crown, Chapters 3–4
St Basil the Great (AD 329–379), On the Holy Spirit (c. AD 375), chapter 27, §§66–67.
On the Holy Spirit, Chapter 27
St Augustine of Hippo (AD 354–430), Against the Fundamental Epistle of Manichaeus (AD 397), 5.6.
Against the Fundamental Epistle of Manichaeus, 5.6
St Augustine of Hippo, On Baptism, Against the Donatists (c. AD 400), IV.24.
On Baptism, Against the Donatists, IV.24
Didache (late first or early second century; exact date disputed), chapter 14.
Didache, Chapter 14
St Justin Martyr (c. AD 100–165), First Apology (c. AD 155), chapter 67.
First Apology, Chapter 67
St Athanasius of Alexandria (c. AD 296–373), Thirty-Ninth Festal Letter (AD 367).
Festal Letter 39
St Robert Bellarmine (1542–1621), De Controversiis, First General Controversy, De Verbo Dei, Book IV, especially chapters 2–3.
Further Reading
St Robert Bellarmine, On the Word of God, Book IV, “On the Unwritten Word of God.” Bellarmine gives one of the classic Catholic theological treatments of divine, apostolic and ecclesiastical traditions.
Online editions of Bellarmine's Controversies
Jean Bainvel, “Tradition and Living Magisterium,” The Catholic Encyclopedia, vol. 15 (1912). A useful pre–Vatican II theological overview explaining the different senses of Tradition and its relationship to the Church's teaching authority.
Tradition and Living Magisterium — Catholic Encyclopedia
Catechism of the Council of Trent, particularly the Preface and sections dealing with the commandments and sacraments.
Catechism of the Council of Trent — Preface
Related Questions
Why Isn't the Bible Alone Sufficient as the Rule of Faith?
What Authority Did Christ Give to His Church?
What Is Apostolic Succession, and Why Does It Matter?
Why Believe the Bible Is the Word of God?
How Do We Know Which Books Belong in the Bible?
Did Christ Intend Christians to Belong to One Visible Church?
Why Must the True Church Be Visible?
Can Catholic Doctrine Develop Without Changing the Faith?