Chapter 17 continues with the Covenant of the Circumcision:
9 Then God said to Abraham, "As for you, you must keep my covenant, you and your descendants after you for the generations to come. 10 This is my covenant with you and your descendants after you, the covenant you are to keep: Every male among you shall be circumcised. 11 You are to undergo circumcision, and it will be the sign of the covenant between me and you. 12 For the generations to come every male among you who is eight days old must be circumcised, including those born in your household or bought with money from a foreigner—those who are not your offspring. 13 Whether born in your household or bought with your money, they must be circumcised. My covenant in your flesh is to be an everlasting covenant. 14 Any uncircumcised male, who has not been circumcised in the flesh, will be cut off from his people; he has broken my covenant."
In the New Covenant of Christianity we will see a new sign of the covenant which replaces circumcision, the sign of Baptism. This sign of the covenant and this action of sealing the covenant is no less significant in Christianity. Notice that Abram, now Abraham, is instructed to circumcise all those born in his household. Later when we see entire households entering into Christianity we have to see this in the light of the new circumcision. The early Church found this significance of Baptism as the new circumcision to be the warrant for infant baptism.
The point is that the covenant is not the culmination of an intellectual argument of assent, but a commitment of faithful servitude as servants and as Mary says "handmaidens" of the Lord. We are instructed to follow and be part of a saved people, a household of the Lord.