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.