The teachings of christ were passed on orally .. The Jews had a strong oral tradition..The epistles of John, Paul, Peter, Jude , and James were all extant too.
Shambles .. I dont know if youve ever debated with Orthodox Christians at all. They are incredibly pedantic.. Sticklers for precision and tradition. almost pharasaically so.
The early church was of this ilk and faithfully preserved the original teachings of Christ by His spirit. Rememberthe original church were a gang of friends and family.. they knew Him well.
This is my Faith.. The Spirit , the Word and the authentic church.
You dont have to use verses.. but if you are intent on debating theology ( You seem very
interested ) then Id give it a go otherwise youre going to be paraprhasing the bible.