The first Christians believed, were baptized, worshiped, and died for Christ before most of the New Testament existed. So where did their faith come from?
Short answer: From the Old Testament read in the light of Christ, and above all from the living preaching of the apostles and the leaders they appointed. Believers "devoted themselves to the teaching of the apostles" (Acts 2:42) years before any New Testament book was written, and disputes were settled by the apostles and presbyters gathered together (Acts 15:6). The New Testament itself grew out of that preaching.
Key verses on the faith before the New Testament
- "They devoted themselves to the teaching of the apostles" (Acts 2:42)
- "Thus faith comes from what is heard, and what is heard comes through the word of Christ." (Romans 10:17)
- "Let what you heard from the beginning remain in you." (1 John 2:24)
- "just as those who were eyewitnesses from the beginning and ministers of the word have handed them down to us" (Luke 1:2)
- "I do not intend to use paper and ink. Instead, I hope to visit you and to speak face to face" (2 John 12)
Scripture quotations are from the New American Bible, Revised Edition (NABRE), © 2010, 1991, 1986, 1970 Confraternity of Christian Doctrine, Washington, D.C. Used by permission. All rights reserved.
What Catholics Actually Teach
The Catechism states the fact plainly: "the first generation of Christians did not yet have a written New Testament, and the New Testament itself demonstrates the process of living Tradition" (CCC 83).
It describes three stages in the formation of the Gospels: the life and teaching of Jesus, then the oral tradition, then the written Gospels. In the second stage, "after the ascension of the Lord, the apostles handed on to their hearers what he had said and done" (CCC 126). To keep that teaching safe, "the apostles left bishops as their successors. They gave them their own position of teaching authority" (CCC 77).
What Catholics do not teach:
- That early Christians had no Scripture. They had the Old Testament, and they received apostolic letters as they were written.
- That the written New Testament is less authoritative than oral teaching. Both carry the one Word of God.
- That Tradition keeps adding new revelations. "No new public revelation is to be expected before the glorious manifestation of our Lord Jesus Christ" (CCC 66).
The Biblical Case
1. Jesus wrote nothing. He sent witnesses.
Jesus never handed His followers a book. He told them, "you will be my witnesses in Jerusalem, throughout Judea and Samaria, and to the ends of the earth" (Acts 1:8). His plan for spreading the truth was people sent with His authority: "Whoever listens to you listens to me" (Luke 10:16).
2. The first Christians lived on apostolic preaching
At Pentecost, the new believers "devoted themselves to the teaching of the apostles and to the communal life, to the breaking of the bread and to the prayers" (Acts 2:42). When persecution came, "those who had been scattered went about preaching the word" (Acts 8:4). As St. Paul asks, "how can they believe in him of whom they have not heard? And how can they hear without someone to preach?" (Romans 10:14).
Most scholars date St. Paul's earliest letters to around AD 50, roughly two decades after the resurrection, and the last New Testament books to near the end of the first century (approximate dates). All that time, the Church was already teaching, baptizing, and celebrating the Eucharist.
3. They read the Old Testament through the apostles' teaching
The first Christians did have Scripture. On the road to Emmaus, "beginning with Moses and all the prophets, he interpreted to them what referred to him in all the scriptures" (Luke 24:27). But the text alone was not enough. The Ethiopian official was reading Isaiah when St. Philip asked if he understood. "How can I, unless someone instructs me?" (Acts 8:30–31).
4. Disputes were settled by the Church
When Christians argued over whether Gentile converts must be circumcised, there was no New Testament to consult. St. Paul and St. Barnabas went "up to Jerusalem to the apostles and presbyters about this question" (Acts 15:2). Their decision opened with, "It is the decision of the holy Spirit and of us" (Acts 15:28), and it was "handed on to the people for observance" (Acts 16:4).
5. The letters assume a faith already received
New Testament letters went to churches that already believed: "I am reminding you, brothers, of the gospel I preached to you, which you indeed received and in which you also stand" (1 Corinthians 15:1). The Romans had become "obedient from the heart to the pattern of teaching to which you were entrusted" (Romans 6:17). Some matters St. Paul left for his visit: "The other matters I shall set in order when I come" (1 Corinthians 11:34).
Even the Gospels were written from what was handed down. St. Luke wrote "so that you may realize the certainty of the teachings you have received" (Luke 1:4). Theophilus had been taught before he had St. Luke's Gospel.
Objections Answered
(a) "They had the Old Testament, and the Bereans tested Paul by it."
At its strongest: St. Luke praises the Bereans because they "examined the scriptures daily to determine whether these things were so" (Acts 17:11). That looks like Scripture alone as the test, even in the apostolic age.
Answer: Catholics agree that Scripture tests teaching. But notice the same verse says they "received the word with all willingness." They were receiving an apostle's spoken preaching and checking it against the Old Testament, which could confirm that "the Messiah had to suffer and rise from the dead" (Acts 17:3). It could not, by itself, tell them which books would form the New Testament, or settle the circumcision question. The apostles' living teaching did that (Acts 15:28).
(b) "Once the New Testament was finished, oral tradition was no longer needed."
At its strongest: Jude speaks of "the faith that was once for all handed down to the holy ones" (Jude 3). Once the apostles wrote that faith down, Scripture replaced the oral stage. Unwritten reports only drift over time.
Answer: We agree revelation is complete (CCC 66). But Scripture never says the handing-on would stop. St. Paul planned for it to continue: "what you heard from me through many witnesses entrust to faithful people who will have the ability to teach others as well" (2 Timothy 2:2). And after the apostles died, the Church still had to discern which books were Scripture. "It was by the apostolic Tradition that the Church discerned which writings are to be included in the list of the sacred books" (CCC 120). (See Who Decided Which Books Are in the Bible?)
(c) "Oral tradition is just a game of telephone."
At its strongest: Stories passed by word of mouth get distorted. Only writing can preserve the truth reliably.
Answer: Apostolic tradition was not a private whisper chain. It was public, repeated in worship, and guarded by appointed teachers: "Guard this rich trust with the help of the holy Spirit that dwells within us" (2 Timothy 1:14). A bishop must be "holding fast to the true message as taught" (Titus 1:9). Above all, Jesus promised the Holy Spirit "will teach you everything and remind you of all that [I] told you" (John 14:26).
The Early Church Agrees
- Pope St. Clement I (St. Clement of Rome) (Letter to the Corinthians, c. AD 96, approximate): "The apostles have preached the gospel to us from the Lord Jesus Christ; Jesus Christ [has done so] from God." Preaching "through countries and cities, they appointed the first fruits [of their labours]... to be bishops and deacons of those who should afterwards believe." (ch. 42)
- St. Papias of Hierapolis (early second century, quoted by Eusebius) asked those who had known the elders "what Andrew or what Peter said." He explains: "For I did not think that what was to be gotten from the books would profit me as much as what came from the living and abiding voice." (Church History 3.39.4)
- St. Irenaeus of Lyons (Against Heresies, c. AD 180) gives the same order the New Testament shows, preaching first and writing after: "We have learned from none others the plan of our salvation, than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith" (3.1.1). Then he asks: "For how should it be if the apostles themselves had not left us writings? Would it not be necessary, [in that case,] to follow the course of the tradition which they handed down to those to whom they did commit the Churches?" He points to believers of his own day who had "salvation written in their hearts by the Spirit, without paper or ink, and, carefully preserving the ancient tradition," held the true faith (3.4.1–2).
Conclusion
The first Christians knew the truth the way Jesus designed: by hearing it from the apostles He sent, reading the Old Testament in light of their teaching, and holding fast within the Church. The New Testament came from that living faith.
If you are Protestant, you already trust that the first-century Church knew the Gospel before it was written down. Ask where that same apostolic teaching lives today. (Related: What Is Sacred Tradition, and Is It Biblical?)
Come home. The apostolic teaching that formed the first Christians before a single Gospel was written still lives today in the Catholic Church, guarded by the successors of the apostles. Christ did not found many churches. He founded one, on St. Peter and the apostles (Matthew 16:18), and that Church is the Catholic Church. "It is through Christ's Catholic Church alone, which is the universal help toward salvation, that the fullness of the means of salvation can be obtained" (CCC 816). If you are a baptized Christian, you already share "a certain, although imperfect, communion" with her (CCC 838). Every truth you already hold is a call to the rest of the way. Christ is calling you into the Catholic Church.
Your next step: Come to Mass this Sunday at your local Catholic church. You can find one near you at MassTimes.org. Everyone is welcome; if you're not yet Catholic, pray with us but don't receive Communion yet. When you're ready to become Catholic, call the parish office and ask about OCIA, the Order of Christian Initiation of Adults. They will walk you through every step. Read our guide: How Do I Become Catholic? Not ready yet? Get our free pocket guide below and keep learning.
FAQ
When was the first New Testament book written? Most scholars place St. Paul's earliest letters, such as 1 Thessalonians, around AD 50. That date is approximate.
Did the first Christians have any Bible at all? Yes. They had the Jewish Scriptures, which Jesus and the apostles interpreted as pointing to Him (Luke 24:27).
Does this mean the Bible is less important? No. Scripture is God's inspired word. The point is that Christ gave His truth to a living Church, which later wrote and recognized the New Testament (CCC 83, 120).
Sources
Scripture (NABRE, bible.usccb.org): Matthew 16:18; Luke 1:2–4; Luke 10:16; Luke 24:27; John 14:26; Acts 1:8; Acts 2:42; Acts 8:4, 30–31; Acts 15:2, 6, 28; Acts 16:4; Acts 17:3, 11; Romans 6:17; Romans 10:14, 17; 1 Corinthians 11:34; 1 Corinthians 15:1; 2 Timothy 1:14; 2 Timothy 2:2; Titus 1:9; 1 John 2:24; 2 John 12; Jude 3.
Catechism of the Catholic Church (vatican.va): 66; 77; 83; 120, 126; 816, 838.
Church Fathers (newadvent.org; Eusebius via ccel.org): Clement of Rome, Letter to the Corinthians 42 (ANF vol. 9); Eusebius, Church History 3.39.4 (Papias) (NPNF2 vol. 1); Irenaeus, Against Heresies 3.1.1 and 3.4.1–2 (ANF vol. 1).