18 Moses went back to Jethro his father-in-law and said to him, "Please let me go back to my brothers in Egypt to see whether they are still alive." And Jethro said to Moses, "Go in peace." 19 And the Lord said to Moses in Midian, "Go back to Egypt, for all the men who were seeking your life are dead." 20 So Moses took his wife and his sons and had them ride on a donkey, and went back to the land of Egypt. And Moses took the staff of God in his hand. 21 And the Lord said to Moses, "When you go back to Egypt, see that you do before Pharaoh all the miracles that I have put in your power. But I will harden his heart, so that he will not let the people go. 22 Then you shall say to Pharaoh, 'Thus says the Lord, Israel is my firstborn son, 23 and I say to you, "Let my son go that he may serve me." If you refuse to let him go, behold, I will kill your firstborn son.'"
24 At a lodging place on the way the Lord met him and sought to put him to death. 25 Then Zipporah took a flint and cut off her son's foreskin and touched Moses'[1] feet with it and said, "Surely you are a bridegroom of blood to me!" 26 So he let him alone. It was then that she said, "A bridegroom of blood," because of the circumcision.
Matthew Henry's Commentary on Exodus 4:18-26
Commentary on Exodus 4:18-23
(Read Exodus 4:18-23)
After God had appeared in the bush, he often spake to Moses. Pharaoh had hardened his own heart against the groans and cries of the oppressed Israelites; and now God, in the way of righteous judgment, hardens his heart against the teaching of the miracles, and the terror of the plagues. But whether Pharaoh will hear, or whether he will forbear, Moses must tell him, Thus saith the Lord. He must demand a discharge for Israel, Let my son go; not only my servant, whom thou hast no right to detain, but my son. It is my son that serves me, and therefore must be spared, must be pleaded for. In case of refusal I will slay thy son, even thy first-born. As men deal with God's people, let them expect so to be dealt with.
Commentary on Exodus 4:24-31
(Read Exodus 4:24-31)
God met Moses in anger. The Lord threatened him with death or sent sickness upon him, as the punishment of his having neglected to circumcise his son. When God discovers to us what is amiss in our lives, we must give all diligence to amend it speedily. This is the voice of every rod; it calls us to return to Him that smites us. God sent Aaron to meet Moses. The more they saw of God's bringing them together, the more pleasant their interview was. The elders of Israel met them in faith, and were ready to obey them. It often happens, that less difficulty is found than was expected, in such undertakings as are according to the will of God, and for his glory. Let us but arise and try at our proper work, the Lord will be with us and prosper us. If Israel welcomed the tidings of their deliverance, and worshipped the Lord, how should we welcome the glad tidings of redemption, embrace it in faith, and adore the Redeemer!