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.
And God told Moses, "When you go back to Egypt, perform miracles for Pharaoh using the power I've given you. But I will make Pharaoh's heart stubborn, so he won't let the people leave."