1. The Lord gave Isaac as he promised (1-6)

Now the Lord gave Isaac to Sarah at the very time God had promised. Abraham was 100 years old. Our God is God of the covenant. He is faithful to keep his promise no matter how impossible it looks to us. Abraham called him Isaac (Laughter) and circumcised him showing his obedience and thanks to God. God is Almighty! Sarah said, "God has brought me laughter, and everyone who hears about this will laugh with me." She praised God for his marvelous hands in having Isaac.

2. Get rid of Ishmael (8-21)

Now Isaac grew and had a feast to be weaned. But Sarah saw that Ishmael was mocking him. She asked Abraham to get rid of him. Abraham was reluctant because Ishmael was his son too. However, God says to listen to Sarah, because it is through Isaac that his offspring will be reckoned. God cannot accept what comes from our own good ideas but only by faith in God's promises. Abraham obeyed God absolutely. He got rid of Hagar and Ishmael. However, God saved the boy and blessed him to be a great nation too.