Exodus 4:21

4:21 The Lord said to Moses, “When you go back to Egypt, see that you do before Pharaoh all the wonders I have put under your control. But I will harden his heart and he will not let the people go.

Exodus 14:17

14:17 And as for me, I am going to harden the hearts of the Egyptians so that they will come after them, that I may be honored because of Pharaoh and his army and his chariots and his horsemen.