There’s a saying in Catholic Apologetics circles: “Sola Scriptura is not scriptural.” It was popularized by former Protestants, who were amazed to find that there’s nothing in Scripture that says that the Bible alone is or ought to be the sole source of religious teaching.
Consider this: it was at least 60 years after Pentecost before the first Gospel was written, and another 1,500 years after that before the invention of the printing press. Is it reasonable to assume that only a few highly privileged souls were saved before the Gutenberg Bible (a Catholic Bible) was printed in 1454? The very suggestion is silly on its face.
Those of us faithful have enough on our hands defending Scripture from the abuse of atheists, who would ask many of the same questions. For instance: how can we believe the Gospels, when they were written at least two generations after the fact? If the reader can answer that question for himself, therein lies the answer to the question of sola scriptura.
For if the Bible alone were necessary to communicate all knowledge which is holy and necessary for salvation, then only those who could read it would benefit from it! Yet we have it from Holy Scripture itself that many of Christ’s teachings would be passed on orally: 1 Thessalonians 2:13, 2 Thessalonians 2:14, 2 Thessalonians 3:6, 1 Corinthians 11:2, 1 Corinthians 15:2, 2 Timothy 2:2, 2 Peter 1:20, and Luke 10:16, for starters. In his letters, St. Paul often quotes from early Christian hymns, as in Ephesians 5:14. Our Lord’s teachings had to be passed down from one generation to the next by word of mouth, and carefully preserved, until they could be recorded in a more permanent form—and little of those original documents have survived to this day. What we’re left with are copies.
Our Lord Himself wrote nothing. So much for faith in only the written word.
There are other examples of Tradition in the Bible. For instance, in 2 Timothy 3:8, St. Paul says “Now as Jannes and Mambres resisted Moses, so these also resist the truth, men corrupted in mind, reprobate concerning the faith.” Well, who are Jannes and Mambres? They’re nowhere to be found in the Old Testament—indeed, nowhere else in the Bible. But they are a part of rabbinic Tradition, and you can still find them in the Jewish Encyclopedia. And Matthew wrote ( 2:23), “And coming he dwelt in a city called Nazareth: that it might be fulfilled which was said by prophets: That he shall be called a Nazarene.” Which prophets said that he should be called a “Nazarene”? Where is that in the Bible? Then there’s Jude 1:9. Where is it written that St. Michael fought with Satan over Moses’ body? Where did Jude get his information? It must have been passed on to him verbally.
Some Fundamentalists, desperate to refute the idea of Tradition, resort to the “grapevine” fallacy, using John 21:22-23 as an example of how messages change meaning once they’ve passed through so many hands. John was following Jesus and Peter, and Peter became jealous. Jesus turned to Peter and said (to use the vernacular), “If he comes with me, what business is it of yours?” This became, after it was repeated, “John will come with me where I go,” which was understood to be the Kingdom of Heaven. But that’s not what Jesus said, and if we finish reading that 23rd verse, John straightens things out for us: “Jesus did not say to him: He should not die; but, So I will have him to remain till I come, what is it to thee?”
So of course meanings can be perverted if the messages are not carefully preserved, but that line of reasoning must extend to the entirety of the Gospels. Can we trust those who wrote the Gospels? What if they got it wrong? What is more important, the message, or the word? Did Judas hang himself, or die by falling? Maybe he hanged himself, and the rope broke; thus did he both hang and eviscerate himself. Does it matter? Is the Bible a history book, or a book of history? Those who cite John 21:22-23 as a “proof text” against Tradition can’t have it both ways.
Oral tradition continues in Mark 3:14, 13:31, 16:15; Luke 10:16, 24:47; Acts 2:3-4, 15:27; Romans 10:8, 17; 1 Corinthians 15:1, 11; Galatians 1:11-12; Ephesians 1:13; "Colossians 1:5; Titus 1:3; 1 Peter 1:25; 2 John 1:12 (“I do not want to use paper and ink. Instead, I hope to visit you and talk with you face to face”); and 3 John 13. In these, the Word of God is “what you heard,” not what you read. St. Paul advises Timothy and others that the Gospel does not die with the Apostles, but lives on. The Gospels hadn’t even been written yet!