And he went out from Pharao exceeding angry. But the Lord said to Moses: Pharao will not hear you, that many signs may be done in the land of Egypt.
And the Lord said to Moses: Go in to Pharao. For I have hardened his heart, and the heart of his servants: that I may work these my signs in him.
But I know that the king of Egypt will not let you go, but by a mighty hand.
And the Lord said to him as he was returning into Egypt: See that thou do all the wonders before Pharao, which I have put in thy hand. I shall harden his heart, and he will not let the people go.