This can be stated in active form. Alternate translation: "as God spreads his grace to many people" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Paul speaks of thanksgiving as if it were an object that could become larger by itself. Alternate translation: "more and more people may give thanks, to the glory" (See: [[rc://en/ta/man/translate/figs-metaphor]])