Exodus 4:22

20Moses took his wife and his sons, and set them on a donkey, and he returned to the land of Egypt. Moses took God’s rod in his hand.

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

22You shall tell Pharaoh, ‘The LORD says, Israel is my son, my firstborn,

23and I have said to you, “Let my son go, that he may serve me;” and you have refused to let him go. Behold, I will kill your firstborn son.’”

24On the way at a lodging place, the LORD met Moses and wanted to kill him.