15 And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be. 16 And I will bless her, and give thee a son also of her: yea, I will bless her, and she shall be a mother of nations; kings of people shall be of her. 17 Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear? 18 And Abraham said unto God, O that Ishmael might live before thee! 19 And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him (Genesis 17:15-19).
With the renaming of Sarah and Abraham, God was emphasizing the importance of the transition from their old life to their new life with God. But this transformation though begun through faith, was still not complete. Abraham still doubted God and had contempt for Him to some extent (he laughed at God). This may sound familiar to us. After all, we know God’s promises and yet often we live as if God’s promises have no merit.
With the renaming of Sarah and Abraham, God was emphasizing the importance of the transition from their old life to their new life with God. But this transformation though begun through faith, was still not complete. Abraham still doubted God and had contempt for Him to some extent (he laughed at God). This may sound familiar to us. After all, we know God’s promises and yet often we live as if God’s promises have no merit.