Then Judah spoke to his daughter-in-law Tamar. He said, “Live as a widow in your father’s home. Wait there until my son Shelah grows up.” Judah was thinking, “Shelah might die too, just like his brothers.” So Tamar went to live in her father’s home.
But Onan knew that the children wouldn’t belong to him. So every time he slept with his brother’s wife, he spilled his semen on the ground. He did it so he wouldn’t provide children for his brother.
Suppose two brothers are living near each other. And one of them dies without having a son. Then his widow must not marry anyone outside the family. Her husband’s brother should marry her. That’s what a brother-in-law is supposed to do.
Go home, my daughters. I’m too old to have another husband. Suppose I thought there was still some hope for me. Suppose I married a man tonight. And later I had sons by him.