God is not omnipotent in the sense that he can do anything.
God can only do those things which are consistent with his nature.
He cannot therefore readily pardon the sinner,
because he is a God of infinite justice.
But neither can he readily punish the sinner,
because he is also a God of infinite mercy.
Here, then, if we may use human language, was the divine dilemma.
How could he pardon the sinner without compromising his justice?
How could he judge the sinner without frustrating his love?
How in the face of human sin could he be at the same time
a God of love and of wrath?
How could he both pardon the sinner and punish the sin?
How could a righteous God forgive unrighteous men without involving himself
in their unrighteousness?
--From "Our Guilty Silence" (London: Hodder and Stoughton, 1967), p. 50.