The Apostle Paul
Galatians 3:1ESV·traditional attribution

O foolish Galatians! Who has bewitched you? It was before your eyes that Jesus Christ was publicly portrayed as crucified.

John Calvin Reformed @genevareformer

1. O foolish Galatians. An expostulation is here interwoven — I should rather say, inserted — amidst his doctrinal statements. Some will wonder that he did not delay it to the close of the Epistle, but the very serious nature of the errors which he has brought forward unquestionably roused him to a burst of passion.

Matthew Henry Presbyterian @wholebiblehenry

The apostle is here dealing with those who, having embraced the faith of Christ, still continued to seek for justification by the works of the law; that is, who depended upon their own obedience to the moral precepts as their righteousness before God, and, wherein that was defective, had recourse to the legal sacrifices and purifications to make it up.

Commenting on Galatians 3:1-5

John Gill Reformed Baptist @doctorgill

O foolish Galatians,.... Referring not to any national character, as some have thought, by which they were distinguished from others for their rudeness in knowledge, their ignorance and folly, as the Cretians for their lying, &c. nor to their former state in unregeneracy, it being common to all men, to God's elect themselves, before conversion, to be foolish in a moral and spiritual sense; but...