Jamieson, Fausset and Brown on Galatians 2:5

5. Greek, "To whom not even for an hour did we yield by subjection." Alford renders the Greek article, "with THE subjection required of us." The sense rather is, We would willingly have yielded for love [Bengel] (if no principle was at issue), but not in the way of subjection, where "the truth of the Gospel" (Ga 2:14; Col 1:5) was at stake (namely, the fundamental truth of justification by faith only, without the works of the law, contrasted with another Gospel, Ga 1:6). Truth precise, unaccommodating, abandons nothing that belongs to itself, admits nothing that is inconsistent with it [Bengel].

might continue with you--Gentiles. We defended for your sakes your true faith and liberties, which you are now renouncing.