15 So then, brothers, stand firm and hold the traditions which you were taught by us, whether by word or by letter. WEB
“stand firm and hold the traditions which you were taught by us” The word tradition means to pass down to another person, in this case, a message which is person-to-person (orally) that it might continue with each generation. What was the message? The answer is found in 1 Thessalonians 2:13. Let’s see what Paul’s tradition was.
1 Thessalonians 2:13
“13 For this cause we also thank God without ceasing, that when you received from us the word of the message of God, you accepted it not as the word of men, but as it is in truth, the word of God, which also works in you who believe.”
The tradition was the same message that was penned as we have it in our Bibles today. There is no missing or secret message of God where one special religious group contains. The Scriptures define itself with what it means. We can rest assured that we have the full message of Jesus Christ.
For more about the word “Tradition” and its meaning, please click on the link: What Does The Word Tradition Mean In Scripture?: Answering A Catholic