Gal 1:1 Paul, an apostle (not from men nor through man, but through Jesus Christ and God the Father who raised Him from the deadAnd he claimed that his gospel likewise was not given to him by man, but he got it directly from Jesus Christ.
Gal 1:11,12 I make known to you, brethren, that the gospel which was preached by me is not according to man. For I neither received it from man, nor was I taught it, but it came through the revelation of Jesus Christ.But how are Paul's claims validated?
When the Jews demanded of him, "What miraculous sign can you show us to prove your authority to do all this?" Jesus answered them, "Destroy this temple, and I will raise it again in three days." John 2:18,19 Speaking of his resurrection. Likewise Nicodemus noted, ."Rabbi, we know you are a teacher who has come from God. For no one could perform the miraculous signs you are doing if God were not with him." John 3:2 Likewise Jesus himself said, "Do not believe me unless I do what my Father does. But if I do it, even though you do not believe me, believe the miracles, that you may know and understand that the Father is in me, and I in the Father." John 10:37,38 Jesus tells us not to believe someone who claims to speak for God, but has no miracles to show for it. Mohammed, for example, is disqualified as a prophet. Miracles are necessary to affirm such a person is speaking for God. Peter said, "Men of Israel, listen to this: Jesus of Nazareth was a man accredited by God to you by miracles, wonders and signs, which God did among you through him, as you yourselves know." Acts 2:22 John records some of Jesus' miracles in his gospel saying, "Jesus did many other miraculous signs in the presence of his disciples, which are not recorded in this book. But these are written that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name." John 20:30,31 Paul also affirmed Jesus in this way to the Athenians, "God has set a day when he will judge the world with justice by the man he has appointed. He has given proof of this to all men by raising him from the dead." Acts 17:31Jesus and his apostles affirm that belief in him should be on the basis of miracles. Jesus' miracles are Jesus' credentials. But Paul himself has these same credentials.
Truly the signs of an apostle were accomplished among you with all perseverance, in signs and wonders and mighty deeds. 2Cor 12:12
Now God worked unusual miracles by the hands of Paul, so that even handkerchiefs or aprons were brought from his body to the sick, and the diseases left them and the evil spirits went out of them. Acts 19:11,12When he went up to Jerusalem to present his gospel to them, this is what silenced his skeptics.
Therefore they stayed there a long time, speaking boldly in the Lord, who was bearing witness to the word of His grace, granting signs and wonders to be done by their hands Acts 14:3
Then all the multitude kept silent and listened to Barnabas and Paul declaring how many miracles and wonders God had worked through them among the Gentiles. And after they had become silent. Acts 15:12,13