I am not assuming that Paul did not have bad days; and I am not assuming that he never uttered a word that was not a mistake – that would not be my assumption. That is not how inspiration works anyway which you can see if you study the history of inspiration, such as prophetic and various kinds of inspiration. Inspiration is a moment-to-moment thing. It is something of the Holy Spirit. It is like John of Patmos when he says “I was in the Spirit on the Lord’s Day and I saw.” He does not say “everyday I’m in the Spirit and whatever I say is God’s truth.” There were times of inspiration. I am perfectly happy with saying there is a lot more truth that was shared by many Christians that did not make it into the canon. It is not a problem.
Why these did make it and others did not make it? It was an oral culture. Only a tiny minority of what was said was ever written down. We are just fortunate and blessed – it is in fact providential – that Paul had to write letters from a distance to his churches because he could not be there and say it to them in person. Otherwise we would not have these letters. Many of these documents are written from a distance. That is why we have them at all. So I take it as a matter of God’s providence. What God wanted was a representative sampling of various different kinds of Christians speaking to the central Christ-event and the truth about Christ in a variety of ways. They were trying to witness to a whole host of different kinds of people – Greeks, Romans, Jews, Scythians, Barbarians, Lydians, men and women; etc. I would call the New Testament the ‘Whitman Sampler’ of the kinds of things that were said and taught about Jesus in the 1st century A.D. There was a variety of audiences to whom the witness needed to come, so it differed. And that’s a good thing.