Acts 7:8

Then He gave him the covenant of circumcision; and so Abraham begot Isaac and circumcised him on the eighth day; and Isaac begot Jacob, and Jacob begot the twelve patriarchs.

1. After the promise came the covenant. A covenant is an agreement between a higher power (God) and a lesser power (man). Often we think of a contract as between equals, but a covenant is one-sided. The higher power states the terms. There is no negotiation. The lesser just accepts or rejects. There is no bargaining or compromise.

2. Circumcision is the sign of the covenant. When Isaac was eight days old, he was circumcised so he would be in covenant with God.

3. After Isaac, Jacob, and the twelve sons (tribes) of Israel. All were circumcised. All were under the covenant with God.