God deals harshly with His servant's sin (circumcision). Not only does this sexual sin disrupt families (Gen 16:6), but here; Abram's adultery with Hagar and unfaithfulness toward God, he must mark himself and all others in the household must pay Abrams price. Abram agrees.
The mark of sin is forever to be remembered. The covenant and forgiveness, is forever. Abram still becomes righteous.