What does Genesis 21:15 mean?
In the previous verse, Abraham sent away Hagar, his slave wife, and Ishmael, his firstborn son. He was obeying the Lord's instruction to do as his wife Sarah had demanded. God's instruction for Abraham to follow Sarah's wishes came with a reassurance that Ishmael would be blessed (Genesis 21:13). This was not Abraham abandoning his son to certain death, or to poverty. Still, it feels harsh to us to see a father send his son away like this.We're told the pair wandered in the wilderness of Beersheba. Abraham had given them bread and a skin of water. If the skin was a goat skin, as was apparently common, it could have held about 3 gallons, or 15 liters, of water. That wouldn't last two people very long in the desert, and now it was gone.
The pair were likely quite dehydrated. From a human perspective, they probably felt they had little hope of survival. Hagar found some bushes and put Ishmael under one of them in the shade. Ishmael was likely about 16 years old.
Genesis 21:8–21 describes the painful departure of Hagar and Ishmael from Abraham's life. Now that Isaac is born, Sarah furiously demands that Abraham cast them out. He is greatly displeased, but is told by God that Ishmael will be protected and blessed. So Abraham obeys the Lord and sends them into the wilderness. God steps in and saves the mother and child. He renews his promise to make Ishmael a great nation in his own right. Ishmael grows up in the wilderness, eventually marrying an Egyptian woman.
The Lord did as He had promised. Sarah, now 90 years old, gives birth to Isaac, the long-awaited child. Her joy sours, though, over a fear that Isaac might have to share an inheritance with Ishmael. In obedience to the Lord, who promises to safeguard Ishmael, Abraham sends him and his mother, Hagar, into the wilderness. God rescues them and renews His promise to make Ishmael a great nation in his own right. Meanwhile, Abimelech, king of Gerar, approaches Abraham to make a permanent treaty between them and their descendants. The agreement includes Abraham's possession of a well, at a place which will become known as Beersheba.
