35 And the heart of Pharaoh was hardened, neither would he let the children of Israel go; as the LORD had spoken by Moses.
Exodus 9:35 Cross References - KJV
Exodus 4:21
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.