No man gave Paul authority to preach and evangelize, which he did before he even met Peter, after being filled with the Spirit of Christ thru a certain devout disciple.
And straightway he preached Christ in the synagogues, that he is the Son of God. (Acts 9:20)
But as part of the body, he was commissioned to do certain missions, even before Acts 15 and not by known apostles:
Now there were in the church that was at Antioch certain prophets and teachers; as Barnabas, and Simeon that was called Niger, and Lucius of Cyrene, and Manaen, which had been brought up with Herod the tetrarch, and Saul. As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them. And when they had fasted and prayed, and laid their hands on them, they sent them away. (Acts 13:1-3)
Likewise in Acts
And his apostleship and preaching being attacked, he finally presented himself to those, "who seemed to be somewhat, (whatsoever they were, it maketh no matter to me: God accepteth no man's person:) for they who seemed to be somewhat in conference added nothing to me: (Galatians 2:6 )
And Paul himself states that
I am become a fool in glorying; ye have compelled me: for I ought to have been commended of you: for in nothing am I behind the very chiefest apostles, though I be nothing. (2 Corinthians 12:11)
I know. The point is the apostles and Paul were united.