24. Now he was on the way, in an inn, that the Lord met him and sought to put him to death.
25. So Zipporah took a sharp stone and severed her son's foreskin and cast it to his feet, and she said, "For you are a bridegroom of blood to me."
26. So He released him. Then she said, "A bridegroom of blood concerning the circumcision."
It can be midrash or anything else