We are reminded that “mercy triumphs over judgment” by James (James 2:13b). We see God's mercy illustrated in the life of Abraham and Sarah. They often made mistakes. They sinned as every person (except Jesus) has sinned (1 John 2:1-2). Yet God did not reject them. He had a plan and purpose for them which he would complete.

Now the LORD was gracious to Sarah as he had said, and the LORD did for Sarah what he had promised.
Genesis 21:1

Abraham and Sarah had to wait for the promised son, Isaac, until they were so old only a miracle could explain his birth. The amazing part of this story is they continued to worship God even though they both laughed at the idea they could have a child at their advanced age (Genesis 17:17; 18:10-12). Their faith did not depend on an immediate answer to their desire for a son.

Their laughter of disbelief was changed to laughter of delight when Isaac was born (Genesis 21:6).

But the testing of their faith was not over. Abraham reluctantly sent away his son Ishmael because God did not intend this son to inherit the promises made to Abraham (Genesis 21:9-13; Galatians 4:30). Although Ishmael was sent away, God did not abandon him and his mother Hagar (Genesis 21: 14-21). All are included in the invitation to participate in the new covenant bought through the blood of Jesus. Everyone in their own order, according to God's timing.

Now the really big test was given to Abraham. He sent away his elder son presumably to never see him again; now he was asked to sacrifice Isaac, the son of promise. We are not told what he was thinking; only that he intended to obey. This was a one-time prophetic event which illustrated God willing to give up his son and his son Jesus being willing to substitute himself in our place, taking our punishment for our sins (Genesis 22:1-19; Romans 4:1-25; Hebrews 11:17-19; 12:1-3). Because Abraham remained faithful he is called “the father of us all” (Romans 4:11).

We fail to appreciate God's gift to us because we simply do not see ourselves as having earned death as a result of turning our backs on God and living however we please with the sorry consequences the whole world is experiencing as a result of rejecting God and his great gift.

Sarah's life comes to an end when she was 127 years old. Abraham buys land in which to bury her and others of his family (Genesis 23:1-20). Abraham's story is not done yet. He still has to ensure the family line will continue by finding a wife for Isaac. God's plan is still in progress.