Then the LORD did exactly what he had promised.
Sarah became pregnant, and she gave a son to Abraham in his old age. It all happened at the time God had said it would.
And Abraham named his son Isaac.
References for Genesis 21:3
Eight days after Isaac was born, Abraham circumcised him as God had commanded.
Abraham was one hundred years old at the time.
And Sarah declared, "God has brought me laughter! All who hear about this will laugh with me.
For who would have dreamed that I would ever have a baby? Yet I have given Abraham a son in his old age!"
As time went by and Isaac grew and was weaned, Abraham gave a big party to celebrate the happy occasion.
But Sarah saw Ishmael -- the son of Abraham and her Egyptian servant Hagar -- making fun of Isaac.
So she turned to Abraham and demanded, "Get rid of that servant and her son. He is not going to share the family inheritance with my son, Isaac. I won't have it!"
This upset Abraham very much because Ishmael was his son.
But God told Abraham, "Do not be upset over the boy and your servant wife. Do just as Sarah says, for Isaac is the son through whom your descendants will be counted.
But I will make a nation of the descendants of Hagar's son because he also is your son."
So Abraham got up early the next morning, prepared food for the journey, and strapped a container of water to Hagar's shoulders. He sent her away with their son, and she walked out into the wilderness of Beersheba, wandering aimlessly.
When the water was gone, she left the boy in the shade of a bush.
Then she went and sat down by herself about a hundred yards away. "I don't want to watch the boy die," she said, as she burst into tears.
References for Genesis 21:16
Then God heard the boy's cries, and the angel of God called to Hagar from the sky, "Hagar, what's wrong? Do not be afraid! God has heard the boy's cries from the place where you laid him.
Go to him and comfort him, for I will make a great nation from his descendants."
Then God opened Hagar's eyes, and she saw a well. She immediately filled her water container and gave the boy a drink.
And God was with the boy as he grew up in the wilderness of Paran. He became an expert archer,
and his mother arranged a marriage for him with a young woman from Egypt.
About this time, Abimelech came with Phicol, his army commander, to visit Abraham. "It is clear that God helps you in everything you do," Abimelech said.
"Swear to me in God's name that you won't deceive me, my children, or my grandchildren. I have been loyal to you, so now swear that you will be loyal to me and to this country in which you are living."
Abraham replied, "All right, I swear to it!"
Then Abraham complained to Abimelech about a well that Abimelech's servants had taken violently from Abraham's servants.
"This is the first I've heard of it," Abimelech said. "And I have no idea who is responsible. Why didn't you say something about this before?"
Then Abraham gave sheep and oxen to Abimelech, and they made a treaty.
But when Abraham took seven additional ewe lambs and set them off by themselves,
Abimelech asked, "Why are you doing that?"
Abraham replied, "They are my gift to you as a public confirmation that I dug this well."
So ever since, that place has been known as Beersheba -- "well of the oath" -- because that was where they had sworn an oath.
After making their covenant, Abimelech left with Phicol, the commander of his army, and they returned home to the land of the Philistines.
Then Abraham planted a tamarisk tree at Beersheba, and he worshiped the LORD, the Eternal God, at that place.
And Abraham lived in Philistine country for a long time.