The story of Abraham and Sarah is at the core of the story of Israel. God called Abraham (Gen. 12:1–3; 15:1–6) and told him that he would make his offspring like the sand of the sea and the stars of the sky. There was just one problem. Abraham and his wife were old.
Sarah, in fact, was well past child-bearing age and did not conceive a child for several years after God’s initial promise (Gen. 16:1–6; Heb. 11:11). Her inability to conceive led to Sarah’s proposal that Abraham have children with her handmaid, Hagar. The result was the birth of Ishmael, whom God told Abraham in no uncertain terms was not the fulfillment of his original promise (Gen. 17:15–21; Heb. 11:17–18). God would enable Sarah to have a child.
God of course kept his promise. Abraham and Sarah had Isaac. God stepped in and made it clear to both Abraham and Sarah that Ishmael was not the fulfillment of his promise. Sarah was the mother God intended for the promised child. To commemorate that miracle, God gave them both a recurring sign of his covenant faithfulness: circumcision (Gen. 17:1–14).
The sign of the covenant meant that every male in Abraham’s household had to be circumcised. The requirement extended to all males born to every family in the nation of Israel because all Israelites were descendants of Abraham through Isaac.
Circumcision seems like an odd sign, not only because of the physical nature of the mark, but also because it seems so one-sided. Of what possible relevance could circumcision have for Israelite women? What’s the point in the first place?
Because of the sexual nature of the sign of circumcision, the ritual mark was an important theological reminder to both genders. The sign would have taken the mind of both men and women back to the fact that they and their children only existed because of divine intervention.
Women would also be reminded of the importance of having husbands who were members of the Israelite community to pass on the bloodline of Abraham, Isaac, and Jacob. Bearing children to gentile men in Old Testament times would have been a covenant transgression unless the man joined the people of Israel (which required circumcision).
As unusual as the sign of circumcision seems to us today, it was a theological statement in its time. This is one important role of ritual—to transport and then fix the mind to a transcendent idea.