John Calvin Commentary Galatians 1:12

"For neither did I receive it from man, nor was I taught it, but [it came to me] through revelation of Jesus Christ." — Galatians 1:12 (ASV)

For I neither received it from man. What then? Should the authority of the word be diminished because someone who has been instructed through men afterwards becomes a teacher?

We must always take into account the weapons with which the false apostles attacked him. They alleged that his gospel was defective and spurious, that he had obtained it from an inferior and incompetent teacher, and that his imperfect education led him to make unguarded statements. They boasted, on the other hand, that they had been instructed by the highest apostles, with whose views they were most intimately acquainted.

It was therefore necessary for Paul to state his doctrine in opposition to the whole world and to rest it on this ground: that he had acquired it not in the school of any man, but by revelation from God. In no other way could he have refuted the reproaches of the false apostles.

The objection that Ananias (Acts 9:10) was his teacher can be easily answered. His divine instruction, communicated to him by direct inspiration, did not make it improper for a man to be employed in teaching him, even if only to give weight to his public ministry. Similarly, we have already shown that he had a direct call from God by revelation, and that he was ordained by the votes and solemn approval of men. These statements are not inconsistent with each other.