Note 1 at Gal. 3:1: Paul is so overwhelmed that these Galatians have rejected the grace of Christ for legalism (see note 1 at Lk. 11:38, p. 322; see note 7 at Mt. 27:6, p. 530) that he is saying these people must be crazy. The Jerusalem Bible says, "Are you people in Galatia mad?" Paul is making no attempt to be polite. He's making it clear that their actions are insane. At best legalism is stupid and at worst it's crazy.

Note 2 at Gal. 3:1: Paul is saying that the Galatians' actions defy logic. There has to be demonic deception involved to turn them from the grace of Christ to legalism. The Living Bible says, "What magician has hypnotized you and cast an evil spell upon you?"

This is Paul "taking off the gloves." He's blasting these people with all he has, leaving no room for compromise. He's doing this because he loves them. Many people would not agree with Paul's harshness, but there's a time for "tough love." We should never relish confrontation, but we should not always avoid it either. There are some issues which are heaven and hell issues which we need to press, regardless of the outcome. Paul viewed legalism as one of those issues.

Note 3 at Gal. 3:1: Paul had depicted the atonement of Christ so vividly to the Galatians that it was as if they were present at His crucifixion. How could they turn from the message that Christ paid it all to a message putting the burden of salvation on their back?

If a person truly understands the message of the cross, then he understands grace. Jesus didn't just make a token sacrifice for us. He paid it all. There's no sacrifice that we can make that will add to or replace the sacrifice of Christ. Preaching that our own holiness is required to receive from God is voiding the sacrifice of Christ (Gal. 2:21).

Therefore, Paul is saying that anyone who has had a clear presentation of the gospel of Christ, as these Galatians had, and who turns away from that grace (see note 5 at Gal. 1:6, p. 1053) back to works (see note 9 at Gal. 2:16, p. 1062) is foolish (see note 1 at this verse), and deceived by the devil (see note 2 at this verse).