Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. Genesis 21:2
The Story
At the prompting of his Wife, Abram had a son by his wife’s slave, Hagar. He named his son Ishmael. [1]
When Abram was 99 years old, God appeared to him, told him he would be the father of many nations and gave him a new name: Abraham. Then God made a Covenant with Abraham. He and his descendants must obey God, and they would be fruitful and possess the land of Canaan forever. Circumcision would be a sign of their covenant. [2]
God also gave Abraham’s wife Sarai a new name. She would be called Sarah. God would bless her, and she would be the mother of nations. Even though she was 90 years old, God assured her that she would bear a son [3].
When Abraham was 100 years old, his promised son Isaac was born [4].
The Significance
Abraham had two sons: One born by the slave woman and one born by the free woman. One born according to the flesh and one made possible by the divine promise. We start like the first son, slaves, in this case, to sin, but because of Jesus, we can be like the free son, children of promise, and children of God. [5]
[1] Genesis 16; [2] Genesis 17:1-14; [3] Genesis 17:15-17; [4] Genesis 21:1-5; [5] Galatians 4:21-31, Galatians 4:7