What happened to "the word of mouth" mentioned in 2 Thessalonians 2:15 ?
So then, brothers and sisters, stand firm and hold fast to the teachings we passed on to you, whether by word of mouth or by letter.
We Catholics know. The letters are the Bible, preserved by the Catholic Church.
What happened to the word of Mouth? What happened to all those things in John 21:25 that could fill more books than the world could hold?
What is “word of mouth” teaching that you are so worried about?
How are you sure anything claimed to be “word of mouth” from the apostles really is?
What is missing out of Scripture that your claimed “word of mouth” teaching needs to fill in?