I do not know if this verse say not every thing Jesus teaching are not documented.
I believe not everything Jesus did was documented, for example, what time Jesus eat, drink, etc, but what is the principal of Jesus teaching was.
And the basic teaching of Jesus is well documented, it is more than enough to know how to save.
After that, yes Jesus talk to Paul on the way to persecute Christian, etc, in Muslim country, some time Jesus talk to Muslim to accept Him. But the basic teaching of salvation was done.
I believe not everything Jesus did was documented, for example, what time Jesus eat, drink, etc, but what is the principal of Jesus teaching was.
And the basic teaching of Jesus is well documented, it is more than enough to know how to save.
After that, yes Jesus talk to Paul on the way to persecute Christian, etc, in Muslim country, some time Jesus talk to Muslim to accept Him. But the basic teaching of salvation was done.
But there was a long time when the church as a whole have not settled on what documents were scripture.
You might be interested in this webpage
http://www.bible-researcher.com/canon5.html