What does Ruth 4:12 mean?
The people and elders of Bethlehem have prayed blessings of fertility on Ruth and Boaz. Now, their words get personal.Ruth and Boaz will have a levirate marriage (Deuteronomy 25:5–6). The first son will live as the heir of Ruth's late father-in-law Elimelech. He will inherit Elimelech's property and position in the clan.
Tamar was also a levirate bride (Genesis 38). She married Er, the oldest son of Judah. Er committed horrible sins, and God struck him down. As is the practice, Judah married Tamar to his next-oldest son, Onan. Onan was to provide an heir for Er, but he refused. Because of this, God struck him down, as well.
Judah's third son, Shelah, was too young to marry. But even when he was old enough, Judah did not give him to Tamar; he was afraid God would take Shelah, as well. By withholding his son, Judah took Tamar's rights for a son. In response, Tamar took off her widow's clothes, veiled herself, and waited where she knew Judah would be traveling. Judah saw her, thought she was a prostitute because of the veil, and propositioned her. She agreed. When Judah heard she was pregnant, he resolved to kill her for adultery. But when she revealed he was the father, he admitted that he was guilty of even greater sin. Tamar gave birth to twin boys, Perez and Zerah. Perez was an ancestor of Boaz.
The people's blessing comes true. Ruth will give birth to Obed. Obed will be the father of Jesse. Jesse will be the father of Israel's greatest king, David (Ruth 4:21–22). And, of course, the Messiah of Israel and Savior of the world will descend from David (Matthew 1:5–16; Luke 3:23–32).