Exodus 4:21 – "And the LORD said unto Moses, When thou goest to return into Egypt, see that thou do all those wonders before Pharaoh, which I have put in thine hand: but I will harden his heart, that he shall not let the people go. "
Exodus 8:15 – "But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the LORD had said. "
From these and similar verses it is sometimes concluded that there is a contradiction here because in some places apparently God hardened the heart of Pharaoh and in other places it is said that Pharaoh hardened his own heart. Is there a mistake in one of these statements or is there possibly another answer to the apparent difficulty?
In a sense, really both statements are true, without there necessarily being a contradiction between them. God had made certain statements to which Pharaoh then reacted in a certain manner. God was not really responsible for the way in which Pharaoh reacted and what he did in response to the word of God. In a typically oriental expression the incident is being referred to as if God had perhaps actively instigated this reaction, even though He really did not do so, but rather the man, Pharaoh, acted in an active manner. By means of an idiomatic expression it is stated that God would harden the heart of Pharaoh, even though this is not really literally true. God did give Pharaoh his choice on how he wanted to react to God's Word and instructions. God did not directly harden Pharaoh's heart, rather Pharaoh did this himself … in reaction to God's Word.
Thus there is not really a contradiction between these statements; however, we must observe that here by means of an idiomatic expression God is said to have done something actively in which He really was only involved by passively letting it happen.