Thomas Aquinas

He begins from what he had said last, showing that God cannot be helped or harmed by our good and evil works, and this is so because of his high character. So he says, "If you sin," against yourself or God, "what harm will you do him?" as if to say: He will suffer no detriment from this. As to the sins which are committed against one's neighbor, he then says, "and if your iniquities are multiplied," by which you unjustly wound your neighbors, "what will you do against him?" as if to say: In no way will he be injured by this. …

Commentary on Job ↗