Then Judah said to Tamar, his daughter-in-law, “Remain a widow in your father’s house, until Shelah, my son, is grown up;” for he said, “Lest he also die, like his brothers.” Tamar went and lived in her father’s house.
Onan knew that the offspring wouldn’t be his; and when he went in to his brother’s wife, he spilled his semen on the ground, lest he should give offspring to his brother.
If brothers dwell together, and one of them dies and has no son, the wife of the dead shall not be married outside to a stranger. Her husband’s brother shall go in to her, and take her as his wife, and perform the duty of a husband’s brother to her.
Go back, my daughters, go your way; for I am too old to have a husband. If I should say, ‘I have hope,’ if I should even have a husband tonight, and should also bear sons,