Acts 22:3

He does not just say "in the school of Gamaliel" but "at the feet of Gamaliel." By these words, he shows his patient endurance, his loving attentiveness, his eagerness to listen and his tremendous reverence for the man.

He does not simply say "the law" but "the law of our fathers." This shows what type of person he had been, someone not ignorant of the law. Now this seems to be said for the benefit of his audience, but in fact, it is an accusation. For what if, with all his knowledge, he had been negligent? What if you have a thorough knowledge of the law but do not fulfill it? You do not love it, then, do you? [Paul] then states plainly that he was a zealot. So after he has delivered a great encomium about himself, he then extends this praise by adding, "just as all of you are today," and thus points out that what they are doing is not just for a human purpose but for their zeal for God. By bestowing this favor on them he also captures their understanding from the beginning.

"I am a man," he says, "which am a Jew:" which thing they liked most of all to hear; "born in Tarsus, a city of Cilicia." That they may not again think him to be of another nation, he adds his religion: "but brought up in this city." He shows how great was his zeal for the worship, inasmuch as having left his native city, which was so great and so remote too, he chose to be brought up here for the Law's sake. See how from the beginning he attached himself to the law. But this he says, not only to defend himself to them, but to show that not by human intent was he led to the preaching of the Gospel, but by a Divine power: else, having been so educated, he would not have suddenly changed. For if indeed he had been one of the common order of men, it might have been reasonable to suspect this: but if he was of the number of those who were most of all bound by the law, it was not likely that he should change lightly, and without strong necessity. But perhaps some one may say: "To have been brought up here proves nothing: for what if thou camest here for the purpose of trading, or for some other cause?" Therefore he says, "at the feet of Gamaliel:" and not simply, "by Gamaliel," but "at his feet," showing his perseverance, his assiduity, his zeal for the hearing, and his great reverence for the man. "Taught according to the perfect manner of the law of the fathers." Not simply, "the law," but "the law of the fathers;" showing that he was such from the beginning, and not merely one that knew the Law. All this seems indeed to be spoken on their side, but in fact it told against them, since he, knowing the law, forsook it. "Yes: but what if thou didst indeed know the law accurately, but dost not vindicate it, no, nor love it?" "Being a zealot," he adds: not simply one that knew it. […]

Educated according to the truth, being a zealot of the paternal law. In Greek it is added more: Being a zealot of God, according to that in Romans: For I bear them witness that they have a zeal for God, but not according to knowledge.

Unsanctified learning made his bonds strong, and furnished him with numerous arguments against the Gospel. Yet when the grace of God had changed his heart, and turned his accomplishments into another channel, he was the fitter instrument to serve God's wise and merciful purposes, in the defense and propagation of Christianity.