Then Judah said to his daughter-in-law Tamar, “Remain a widow in your father’s house until my son Shelah grows up,” for he feared that he too would die, like his brothers. So Tamar went to live in her father’s house.
But since Onan knew that the offspring would not be his, he spilled his semen on the ground whenever he went in to his brother’s wife, so that he would not give offspring to his brother.
“When brothers reside together and one of them dies and has no son, the wife of the deceased shall not be married outside the family to a stranger. Her husband’s brother shall go in to her, taking her in marriage and performing the duty of a husband’s brother to her,
Turn back, my daughters, go your way, for I am too old to have a husband. Even if I thought there was hope for me, even if I should have a husband tonight and bear sons,