It is assumed that if God is omnipotent he can do anything; but this is not strictly true. What God’s omnipotence does mean is that nothing can obstruct him, nothing can prevent his being fully and eternally himself. But this means that it is actually a part of his omnipotence that God does not contradict himself. He is free to determine the manner of his own working; and in fact, as we know from revelation, he has chosen to work in such a way that we can interfere, and interfere very drastically, with his creation. God knows we can never really be fully satisfied with any world of our own devising, so that it will always be vulnerable to his influence in one way or another; and God exploits this to the full. But he always respects the freedom and independence that he has given us.

—Simon Tugwell, Prayer