John Chrysostom

"And they glorified God in me." See here again how accurately he observes the rule of his humility; he says not, they admired me, they applauded or were astonished at me, but ascribes all to Divine grace by the words, "they glorified God in me."

Homily on Galatians 1 ↗

Theophylact of Ohrid

And this is a sign of modesty. For he did not say: they marveled at me, they admired me, but ascribed everything that happened to the action of grace. For "they glorified God because of me," who truly does all things.

Commentary on Galatians ↗

Oecumenius

— [PHOTIUS] "and they glorified God in me." He did not say, "They praised me," or "They glorified me," but, "they glorified God," he says. For all that which was in me, he says, was of God's grace. "in me," that is, on account of me. "glorified God in me," not this or that teacher, but God himself. He was the one who revealed to me and taught the preaching.

Commentary on Galatians ↗

Thomas Aquinas

Thirdly, how he was approved by them, because "they glorified God in me," i.e., in my conversion they glorified Him Who converted me by His grace: "The beast of the field shall glorify me" (Is 43:20).

Commentary on Galatians ↗