Genesis 17:11

And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.

Circumcision is the token of the covenant between God and Abraham and his descendants, the sign and pledge that confirmed and made the covenant sure, ratifying, authenticating, securing and making it stable, so that those without the token were cut off. The word for token also means a memorial, reminder or remembrancer, and sign, mark and seal are used in Scripture as synonymous and of like signification. It was an institution and rite, a sign in the flesh in contrast to the Sabbath as a sign in the mind.

The rite was a circle cut in the flesh, signifying that God had cut them out and separated them from all nations as His peculiar treasure, marking them as devoted to His service and accepted by Him. By receiving it they solemnly agreed to fulfill their part of the covenant, to remain separate from other nations and from idolatry, to be perfect, and to obey God's law. That separation was meant to protect them from intermarriage with heathen peoples, which would lead them to lose reverence for God and His law and to fall into idolatry and rebellion. Their failure to keep the pledge, shown in mingling with other nations and forming alliances and adopting heathen practices, cost them much of their holy and distinctive character.

Their unfaithfulness caused their sojourn and bondage in Egypt, where famine drove them and where intercourse with idolaters and forced submission to the Egyptians further corrupted the divine precepts. Yet God still kept His covenant with Abraham and allowed their oppression to turn them back to Him and His government. The ordinance was necessary because they failed to keep God's law, the law given to Adam after his fall, preserved in the ark by Noah, and observed by Abraham.

If Abraham's descendants had kept the covenant of which circumcision was the token or sign, they would never have been seduced into idolatry nor suffered bondage in Egypt, they would have kept God's law in mind, and there would have been no necessity to proclaim the law from Sinai, engrave it on tables of stone, and guard it by the definite judgments and statutes given to Moses. Circumcision of a son was a condition for receiving the blessings of the covenant, so neglecting this known requirement showed disregard for God's command. Moses's failure to circumcise his youngest son brought a divine warning, and after Zipporah performed the rite he was permitted to continue his mission, since such neglect by Israel's chosen leader could weaken the people's respect for God's precepts.