So when people post here that the Bible was canonized 400 years before the Catholic Church came into being it really doesn't make any historical sense to me.
Same old same old.
Evidence can be gleaned from Josephus (36-100 A.D.) about the canon of our present Bible or at least the 39 books of the OT that we presently use without the apocrypha.
Evidence can be gleaned from other versions concerning the NT: Itala, Peshitta, Syriac, all of which existed long before 300 A.D.
Evidence can be internally from the Bible itself that the Apostles were not ignorant and foolish men as the Pharisees accused them, but were very learned, filled with the Holy Spirit and were able to teach the early believers which books were inspired and which were not. They became canonized "hot off the press." Don't you believe Paul knew when he was writing Scripture and when he was not. The OT prophets certainly did.
Amos 7:14-16 Then answered Amos, and said to Amaziah, I was no prophet, neither was I a prophet's son; but I was an herdman, and a gatherer of sycomore fruit:
15 And the LORD took me as I followed the flock, and the LORD said unto me, Go, prophesy unto my people Israel.
16 Now therefore hear thou the word of the LORD: Thou sayest, Prophesy not against Israel, and drop not thy word against the house of Isaac.
Amos 7:17 Therefore thus saith the LORD; Thy wife shall be an harlot in the city, and thy sons and thy daughters shall fall by the sword, and thy land shall be divided by line; and thou shalt die in a polluted land: and Israel shall surely go into captivity forth of his land.
Amos was nothing more than a farmer and a shepherd, but he knew what he was speaking was inspired--of God.
Paul was probably the most educated man on the face of the known world at that time. I think he knew when God was speaking to him; what books were inspired and which were not. Yet you take him as an ignorant fool!!