Exodus 4:18-23

18So Moses went, returned to his father-in-law Jethro and said to him, “Please let me go, so I may return to my kinsmen who are in Egypt and see whether they are still alive.” Jethro said to Moses, “Go in peace.”

19Then Adonai said to Moses in Midian, “Go, return to Egypt, for all the men that sought your life are dead.”

20So Moses took his wife and his sons, set them on a donkey and returned to the land of Egypt. Moses took the staff of God in his hand.

21Adonai said to Moses, “When you go back to Egypt, see that you do all the wonders before Pharaoh that I have put in your hand. Still, I will harden his heart, and he will not let the people go.

22You are to say to Pharaoh, “This is what Adonai says: ‘Israel is My son, My firstborn.

23So I have said to you, Let My son go, that he may serve Me, but you have refused to let him go. Behold, I will slay your son, your firstborn.’”