The text of Genesis 21:1-21 tells us that God’s promises to Abraham and Sarah were eventually fulfilled in the birth of the promised son, Isaac. While the story has been concerned with Abraham’s struggle to believe the Lord’s promises, on the other hand, the story also emphasizes the certainty of God’s faithfulness. He did not fail to accomplish what He promised. Although the birth of Isaac created issues for Sarah, Hagar and Ishmael, God’s mercy and grace were still not out of the picture.