In chapter 20, Father of Multitudes pulls his trick of passing Princess off as his sister (it worked so well in Egypt). The King of Gerar, where Father of Multitudes is hanging out, takes Princess for his own. She must have been one hot ninety year old woman, let me tell you. I'm beginning to suspect that maybe princess was in her thirties or early forties and still looking good. After all, she hadn't entered menopause.
God tells the King of Gerar in a dream that Princess is Father of Multitude's wife and that he had better restore her to her husband. The king asks why Father of Multitudes would pull such a stunt. The answer is that Father of Multitudes was always afraid that someone would kill him on account of his hot wife. Besides, Princess was technically his half sister (he was her brother by another mother), so it wasn't really lying. This tells me that Father of Multitudes didn't put much stock in God's prediction/promise that he would have a good long life.
In chapter 21, Princess gives birth to He Laughs. She asks Father of Multitudes to get rid of Hagar and Ishmael, and God assures him that this is the right thing to do. Don't worry, God says, I will make of Ishmael a great nation. So Father of Multitudes sends Hagar and his oldest son into the wilderness with some bread and a skin of water. They are at the point of death when God's angel intercedes and shows her a well of water. Everything turns out great for Ishmael. He becomes a great archer and marries an Egyptian.
This story hits home for me, not just because it's another story of a breach of male promogeniture. I was abandoned by my father at about the same age as Ishmael, and my father had a son whom he loved and raised at about the same time in my life that He Laughs was born in Ishmael's life. I'm sure a lot of deadbeat dads take comfort in this story. I did okay without a dad. Just like Ishmael.
Anyway the rest of the chapter involves a covenant between Father of Multitudes and the King of Gerar that the King and his progeny will not be treated falsely on account of the kindness the King had shown. Also, they stipulated that Father of Multitudes had dug the well at Beersheba.
What I take from these stories is that Father of Multitudes was kind of a douche, but God chose him anyway.