God can do all things that are possible (Matt. 19:26). He cannot do what is, for him, impossible, including to sin or to create logical impossibilities (e.g., square circles, mathematical errors, rocks too heavy for him to lift). While God can do things that are impossible for man (Luke 18:27), he cannot do what is impossible for himself. This does not mean that God is not omnipotent; it means only that his power does not negate itself.