Mark 12:19
"Teacher, Moses wrote for us that if a man's brother dies and leaves a wife but no child, he should marry the widow and have children for his brother.
Genesis 38:8
So Judah instructed Onan, "You are to have sexual relations with your dead brother's wife, performing the duty of a brother-in-law with her, and have offspring for your brother."
Deuteronomy 25:5-10
"When two brothers are living together and one of them dies without leaving a son, his widow must not be married outside the family to a foreigner. Instead, the brother-in-law must go to her, take her as his wife, and by doing so perform the duty of a brother-in-law.
Ruth 1:11-13
But Naomi responded, "Go back, my daughters. Why go with me? Are there still sons to be born to me as future husbands for you?
Ruth 4:5
Boaz continued, "On the very day you buy the field from Naomi, you're also "buying" Ruth the Moabite woman, the wife of her dead husband, so the family name may be continued as an inheritance."