John Chrysostom — on Gal 1:1 (Homily on Galatians 1)

“As they disparaged his doctrine, saying it came from men, while that of Peter came from Christ, he immediately addresses himself to this point, declaring himself an apostle "not from men, neither through man." It was Ananias who baptized him, but it was not he who delivered him from the way of error and initiated him into the faith; but Christ Himself sent from on high that wondrous voice, whereby He inclosed him in his net. For Peter and his brother, and John and his brother, He called when walking by the seaside, but Paul after His ascension into heaven. And just as these did not require a second call, but straightway left their nets and all that they had, and followed Him, so this man at his first vocation pressed vigorously forward, waging, as soon as he was baptized, an implacable war with the Jews. In this respect he chiefly excelled the other Apostles, as he says, "I labored more abundantly than they all;" at present, however, he makes no such claim, but is content to be placed on a level with them. Indeed his great object was, not to establish any superiority for himself, but, to overthrow the foundation of their error.”