Covenant of Circumcision:

After Abram had sojourned in the land of promise twenty-four years, the Lord made a covenant with him and changed his name to Abraham (Genesis 12:4-5; Genesis 17:1-5). The Lord proposed to make of him a great nation and to perpetuate the covenant through his offspring (Genesis 17:6-7). Birth and purchase were the conditions of membership in this covenant (Genesis 12:13). Circumcision was,

1. a visible mark in the flesh;
2. it affected only the males of Abraham's family;
3. the children were circumcised on the eighth day;
4. and the uncircumcised were to be cut off from the covenant (Genesis 17:6-14).