Then Judah said to his daughter-in-law Tamar, “Return to your father’s home. Live as a widow until my son Shelah grows up.” He thought that this son, too, might die like his brothers. So Tamar went to live in her father’s home.
But Onan knew that the descendant wouldn’t belong to him, so whenever he slept with his brother’s widow, he wasted his semen on the ground to avoid giving his brother a descendant.
When brothers live together and one of them dies without having a son, his widow must not marry outside the family. Her husband’s brother must marry her and sleep with her. He must do his duty as her brother-in-law.
Go back, my daughters. Go, because I am too old to get married again. If I said that I still have hope. … And if I had a husband tonight. … And even if I gave birth to sons,