Exodus 4:23-26
English Standard Version
24At a lodging place on the way the Lord met him and sought to put him to death.
25Then Zipporah took a flint and cut off her son 's foreskin and touched Moses ' feet with it and said, "Surely you are a bridegroom of blood to me!"
26So he let him alone. It was then that she said, "A bridegroom of blood," because of the circumcision.