Exodus 4:20-21

20So Moses took his wife [Zipporah] and his sons [Gershom and Eliezer] and seated them on donkeys, and returned to the land of Egypt. Moses also took the staff of God in his hand.

21The Lord said to Moses, “When you return to Egypt, see that you perform before Pharaoh all the wonders (miracles) which I have put in your hand, but I will harden his heart and make him stubborn so that he will not let the people go.