What does Genesis 21:5 mean?
Abraham's age at the time of Isaac's birth is given to emphasize that this was a supernatural work of God. This also reminds us that it has been less than a year since God had told Abraham and Sarah they would have a son. Both had laughed at the very idea of it (Genesis 17:17; Genesis 18:12), but even though Abraham was 100 years old, the day finally arrived.God had kept His impossible, laughable, beautiful word. Even though Abraham and Sarah were well beyond the normal age of conception, and Sarah had been barren for her entire life, God provided them with a natural-born son.
