Christians don’t play the “sola scriptura” game, we follow Paul in 2 Thessalonians 2:15.
the Church is the evidence of this Apostolic teaching.
So, what traditions were those and how do you know?
Please cite sources to back up your contention.
That is whether they were taught by word of epistle. Not all had access to written material. Those scrolls were a little hard to duplicate on a moments notice when a new church was started or a new person was converted. The Catholic Church used that technique to deceive the people for many years. Thank God for the Gutenberg press right. That nonsense of decieving people because of no access to written word was over when printing presses came into being. Notice that coincided with the Reformation.
2 Thessalonians 2:15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.