Galatians and Romans
It seems to me that Paul has much theology to teach in both the letters to the Galatians and to the Romans. I believe that both books are very similar, only that here Paul is MAD. When he gets mad, he is able to get 16 chapters into 6 chapters.
You foolish Galatians, who has bewitched you? This foolishness does not refer to lack of intelligence, but to lack of obedience (Luke 24:25; 1 Timothy 6:9; Titus 3:3). Paul expressed his shock, surprise, and outrage at the Galatians’ defection.
The Judaizers, the Jewish false teachers were plaguing the Galatian churches. The word "bewitched" may not assume magic, but they were charmed or misled by flattery and false promises. The term suggests an appeal to the emotions by the Judaizers.
Galatians 3:1–3New American Standard Bible: 1995 Update
You foolish Galatians, who has bewitched you, before whose eyes Jesus Christ was publicly portrayed as crucified?
This is the only thing I want to find out from you: did you receive the Spirit by the works of the Law, or by hearing with faith?
Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh?