Exodus 4, 22 – 26 „So you will say to Pharaoh, Thus says the LORD: Israel is my son, my firstborn. 23I said to you: Let my son go, that he may serve me. Since you refused to let him go, I will kill your son, your firstborn. 24On the journey, at a place where they spent the night, the LORD came upon Moses and sought to put him to death. 25But Zipporah took a piece of flint and cut off her son’s foreskin and, touching his feet, she said, Surely you are a spouse of blood to me. 26So God let Moses alone. At that time she said, A spouse of blood, in regard to the circumcision”.