Exodus 4:20-26

20So Moses took his wife and sons, put them on a donkey, and headed back to the land of Egypt. In his hand he carried the staff of God.

21And the Lord told Moses, “When you arrive back in Egypt, go to Pharaoh and perform all the miracles I have empowered you to do. But I will harden his heart so he will refuse to let the people go.

22Then you will tell him, ‘This is what the Lord says: Israel is my firstborn son.

23I commanded you, “Let my son go, so he can worship me.” But since you have refused, I will now kill your firstborn son!’”

24On the way to Egypt, at a place where Moses and his family had stopped for the night, the Lord confronted him and was about to kill him.

25But Moses’ wife, Zipporah, took a flint knife and circumcised her son. She touched his feet with the foreskin and said, “Now you are a bridegroom of blood to me.”

26(When she said “a bridegroom of blood,” she was referring to the circumcision.) After that, the Lord left him alone.