A levirate marriage is literally a “marriage with a brother-in-law.” The word levirate, which has nothing to do with the tribe of Levi, comes from the Latin word levir, “a husband’s brother.” In ancient times, if a man died without a child, it was common for the man’s unmarried brother to marry the widow in order to provide an heir for the deceased. A widow would marry a brother-in-law, and the first son produced in that union was considered the legal descendant of her dead husband.
We see a couple of examples in the Bible of levirate marriage. The first is the story of Tamar and Onan in Genesis 38. Tamar had been married to Er, a son of Judah. Er died, leaving Tamar childless (Genesis 38:6–7). Judah’s solution was to follow the standard procedure of levirate marriage: he told Er’s brother Onan, “Sleep with your brother’s wife and fulfill your duty to her as a brother-in-law to raise up offspring for your brother” (verse 8). Onan was more than willing to sleep with Tamar, but, unfortunately, he had no desire to have a child with her: “Onan knew that the child would not be his; so whenever he slept with his brother’s wife, he spilled his semen on the ground to keep from providing offspring for his brother” (verse 9). In other words, Onan was taking selfish advantage of levirate marriage. He wanted sex with his sister-in-law, but he purposefully avoided impregnating her. God called Onan’s actions “wicked” and killed him (verse 10).
Levirate marriage became part of the Law in Deuteronomy 25:5–6. There, the Israelites are commanded to care for women whose husbands died before they had children. An unmarried brother of the deceased man bore a responsibility to marry his sister-in-law: God called it “the duty of a brother-in-law” (Deuteronomy 25:5). God’s purpose for levirate marriage is stated: “The first son she bears shall carry on the name of the dead brother so that his name will not be blotted out from Israel” (verse 6). In ancient Israel the passing on of the family name and the inheritance within a tribe were vitally important (see Numbers 36:7 and 1 Kings 21:3).
Another example of levirate marriage in the Bible is the story of Ruth and Boaz. Ruth’s first husband died without leaving a child (Ruth 1:1–5). Later, Ruth met a rich landowner named Boaz in Bethlehem, and he happened to be a relative of Ruth’s late husband (Ruth 2:20). Ruth asked Boaz to be her “kinsman-redeemer”; that is, to marry her and preserve the land her husband had owned (Ruth 3:9). Boaz agreed but informed Ruth that there was one other relative of nearer kin; the obligation to marry Ruth and redeem her land fell on him first (verse 12). As it turned out, the nearer relative officially transferred his right of redemption to Boaz, clearing the way for Boaz to marry Ruth and “maintain the name of the dead with his property” (Ruth 4:5).
In Matthew 22, Jesus is confronted by the Sadducees with a convoluted question based on the Law’s requirement of levirate marriage: “Moses told us that if a man dies without having children, his brother must marry the widow and raise up offspring for him. Now there were seven brothers among us. The first one married and died, and since he had no children, he left his wife to his brother. The same thing happened to the second and third brother, right on down to the seventh. Finally, the woman died. Now then, at the resurrection, whose wife will she be of the seven, since all of them were married to her?” (Matthew 22:24–28). Jesus cuts through the hypothetical and teaches the reality of the resurrection (verses 29–32).
Levirate marriage has fallen out of favor in modern Judaism and is more or less an extinct practice today. But its existence among the ancient Israelites, even before the Law of Moses, shows the importance placed on continuing the family line and preserving one’s divinely appointed inheritance.