Hello Jero (
@Jero Jones),
WELCOME TO CF 
As far as what we know about Paul coming from Paul, that is true, but only in part, as we also have testimony about Paul from Luke, the human author of Luke and Acts, from some of the Apostles, like Peter, and from the mouth of the risen Lord Jesus Himself (I'll post a couple of quotes from others about Paul at the bottom of this post).
Since you are a humanist, it may be helpful for you to understand that Christians and the historic Christian church have always held that the Bible is the very word of God Himself, that it is His
inspired or literally, "
God-breathed" word to us .. e.g.
2 Timothy 3:16-17, and that its writing (by its 40+ human authors) was overseen (superintended) by the Holy Spirit, from Genesis all the way to Revelation, every
jot and tittle, that is .. e.g.
2 Peter 1:20-21.
Therefore, the Epistles (of Paul and others) are considered to be no less and no more Holy Scripture than the Gospels and the Old Testament are.
God did this to make sure that His word, the Bible (which has been His principal means of communicating with His people for millennia now), said EXACTLY what He wanted it to say, for our sake.
I'm sure that you'd like to discuss this further, so it would probably be best for you to start a new thread and post several of Paul's statements that you disagree with there (and why) so that we can see exactly what you are talking about.
May God bless you as you seek to find Him and know Him!!
--David
p.s. - here's a verse and a short passage from others about the Apostle Paul if you'd care to read them (there are more, but this should do for now).
The first is from the Lord Jesus Himself. He was speaking about Saul (soon to be Paul) with Ananias, just before Paul regained his sight, was baptized (following his conversion) and began to preach Christ.
Acts 9
15 The Lord said to Ananias, “Go, for he (Saul/Paul) is a chosen instrument of Mine, to bear My name before the Gentiles and kings and the sons of Israel.
Next is some of what the Apostle Peter has to say about him, in this case, about both Paul, and about the nature of the Epistles that he wrote in the Bible (that they were indeed, Holy Scripture, along with the rest of the Holy Bible).
2 Peter 3
15 Consider that our Lord’s patience brings salvation, just as our beloved brother Paul also wrote you with the wisdom God gave him.
16 He writes this way in all his letters, speaking in them about such matters. Some parts of his letters are hard to understand, which ignorant and unstable people distort, as they do the rest of the Scriptures, to their own destruction.
