It is after Moses is safe from those who sought his life that the is commissioned to return to Pharaoh. The Lord tells him “Thus says the LORD: "Israel is My son, My firstborn. So I say to you, let My son go that he may serve Me. But if you refuse to let him go, indeed I will kill your son, your firstborn” (Exodus 4:22-23).

In verses.22-26 there are three father/son relationships referred to: (1) God as the Father of Israel, His firstborn son (vs. 22-23); (2) Pharaoh and his firstborn son (v. 23b); and (3) Moses and his own son (possibly the firstborn Gershom) who needed to be circumcised.

In v. 24 Moses, Zipporah, and their two sons Gershom and Elieazar are on their way to Egypt.  “And it came to pass on the way, at the encampment, that the LORD met him and sought to kill him.”The Lord meets Moses at their lodging place and was intent to kill him (we do not know how, possibly through a sickness or a more direct means). The question is why?

God could not have Moses be the deliverer of the Hebrew people while he was being disobedient to the Abrahamic covenant, something required of every Hebrew male. To dishonor that sign and seal of the covenant was sinful to a Hebrew, Gen 17:10: “This is My covenant which you shall keep, between Me and you and your descendants after you: Every male child among you shall be circumcised.” Gen 21:4: “Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him.”

The covenant God had made with Abraham and reiterated to the patriarchs and through Moses had a sign. Circumcision was the sign of the Abrahamic covenant, it was the evidence of the parents’ faith in the promise of God to Abraham. That through his seed blessings would come to Israel and to the whole world (Gen. 12:1-3). As a testimony of the parents’ faith in God’s covenant promise, every male in Israel was commanded to be circumcised:(Gen. 17:9-14). It separated Israel from the other nations.

The Midianites did not practice circumcision and Zipporah obviously didn’t like it, this could be why Moses held off from doing this. This may also be why Zipporah instinctively knew why God was seeking to kill Moses. Moses’ life was spared by the quick action taken by his wife Zipporah who unwillingly does this action herself to save her husband. She took a flint knife (Josh. 5:2-3), circumcised her son, and touched Moses with the foreskin, with the rebuke, “Surely you are a bridegroom of blood to me.”

For Moses to serve God and be Israel’s deliverer the Abrahamic covenant needed to obey first.Gen.17. How could Moses go to Egypt and tell the Israelites that God was about to fulfill His promises, based upon His covenant, when Moses had not yet circumcised his son in obedience to the same covenant ( if this son is his firstborn, he had had many years to do it). This relates to the message God gave Moses to give to Pharaoh that Israel being His son, his firstborn is to be set free.  It should have stirred Moses into remembrance of his covenant obligation to his firstborn son. Moses wrote this book and could have omitted this part of his neglect. But he does not, showing that God requires obedience from his leaders, and that Moses was honest and open to write both the right and the wrong of his life.