The Covenant Confirmed

This week we will look at the final step of the Abrahamic covenant: God's promise that Abraham will have a son by Sarah, and his name will be Isaac. Notice that this is the chapter where God names all three of them. No longer will Abram and Sarai be known for who they were. Now they will be known for what God will make them. The gift that comes with this covenant is offspring and a land for them to possess, but the promise is amplified in this chapter. Not only will there be offspring as numerous as the stars, but kings will come from these two and all the land of Canaan will be their dominion. God promises that Sarah herself will bear a child in one year's time and that his name will be Isaac ("he laughs"). There will be no more misunderstanding of how the promises in chapter 12 and chapter 15 will be brought about: God has made it clear. And all of that is what God will do (notice "I will establish my covenant"). But God also gives Abraham his own responsibility to keep as part of this covenant: all the male offspring are to be circumcised on the eighth day as a sign of the covenant. This is the physical sign that will set apart the people of God's covenant from those who are outside of it. Abraham responds in faith and obedience and all the males in his household are circumcised on that very day. This doesn't mean that Abraham's faith and obedience will never waver, but it does show us that God's sovereign plan to crush the head of the serpent through the offspring of Adam and Eve will continue through the line of Abraham.