Exodus 4:24
22 You must say to Pharaoh, ‘This is what the Lord has said, “Israel is my son, my firstborn, 23 and I said to you, ‘Let my son go that he may serve me,’ but since you have refused to let him go, I will surely kill your son, your firstborn!”’” 24 Now on the way, at a place where they stopped for the night, the Lord met Moses and sought to kill him. 25 But Zipporah took a flint knife, cut off the foreskin of her son and touched it to Moses’ feet, and said, “Surely you are a bridegroom of blood to me.” 26 So the Lord let him alone. (At that time she said, “A bridegroom of blood,” referring to the circumcision.)
Onkelos Exodus 4:24
22 And thou shalt say unto Pharoh, Thus said the Lord; Israel is My son, My firstborn. 23 And I say unto thee, Let My son go, that he may serve before Me; and if thou refuse to send him away, behold, I will kill thy son, thy firstborn. 24 And it was in the way, at the place of lodging, that the Angel of the Lord met him, and sought to kill him. 25 And Zipporah took a stone, and circumcised the foreskin of her son, and approached before him, and said, On account of the blood of this circumcision let my husband be given (back) to me. 26 And when he had desisted from him, she said, But for the blood of this circumcision my husband would have been condemned to die.
Notes and References
"... A strange incident occurs on the way to Egypt (vv. 24–25). The angel of the Lord meets Mōusēs and threatens to kill him (v.24). Sepphōra intercedes by circumcising her son (v. 25), somehow averting her husband’s death. BS designates this among the more enigmatic pericopae in the Heb. Bible. It is not even mentioned by Philo or Josephus, and takes on new meaning in LXX Exod ... The subject is the ἄγγελος Κυρίου, “angel of the Lord.” This reading is affirmed by Targum, Targ Neof I (Targ Ps-J has “destroying angel”; cf. Jub. 48.2 where it is Mastemah; Propp 1999), though the MT reads יְהוָה and makes no mention of an “angel.” ..."
Gurtner, Daniel M. Exodus: A Commentary on the Greek Text of Codex Vaticanus (pp. 230-231) Brill, 2013