The law of kinsman-redeemer is extremely important for Christology. It rose out of practical purposes when a man named Zelophehad died. He had no sons but only daughters, and the law of Israel was that the father’s sons would inherit all he had. But Zelophehad had no sons; he only had daughters, and five of them. So, who would receive Zelophehad’s inheritance? The daughters were wise enough to see that it only made sense they receive the inheritance since their father had no sons. It’s common sense. Yet Moses was unclear about what to do, as there were no laws about such a situation. There was, of course, Leviticus 25:25 that spoke of similar kinsman-redemption, but this regarded the issue of someone’s brother becoming poor and selling parts of his property, not the issue of a father dying with no sons. So, Moses did the wise thing by seeking the Lord, and He gives him the law of kinsman-redeemer:
“The daughters of Zelophehad are right. You shall give them possession of an inheritance among their father’s brothers and transfer the inheritance of their father to them. And you shall speak to the people of Israel, saying, ‘If a man dies and has no son, then you shall transfer his inheritance to his daughter. And if he has no daughter, then you shall give his inheritance to his brothers. And if he has no brothers, then you shall give his inheritance to his father’s brothers. And if his father has no brothers, then you shall give his inheritance to the nearest kinsman of his clan, and he shall possess it. And it shall be for the people of Israel as a statute and rule, as the LORD commanded Moses.'”vv. 5-11
The next time we see a situation like this isn’t until the Book of Ruth. Naomi marries a man named Elimelech and they have two sons, Mahlon and Chilion, who marry Midianite women named Orpah and Ruth, respectively. At some point, though, Elimelech dies, which means whatever he had would’ve gone to his two sons; and then Mahlon and Chilion die, leaving the women with nothing (Ruth 1:1-5). This is why the story of Ruth and Boaz are so important because Boaz was one of Elimelech’s living relatives. He had a closer relative than Boaz, which is why when Ruth proposed to him, he sought to fulfil the law of kinsman-redeemer first through this closer relative, but this kinsman rejects his duty because he’s worried about losing his own inheritance if he marries Ruth (3:1-4:6). So, Boaz fulfils his duty as kinsman-redeemer by marrying Ruth. This is hugely significant genealogically. Boaz was part of the tribe of Judah through Perez (Judah and Tamar’s son, Genesis 38), and Ruth and Boaz fathered Obed, who fathered Jesse, who fathered David, and on to the birth of Jesus (4:18-22; Matthew 1:1-17, Boaz listed in v. 6).
Jesus thus became our Kinsman-Redeemer, just like His great-grandfather (x28) Boaz before Him. Without a kinsman-redeemer, Naomi, Ruth, and the daughters of Zelophehad would’ve died. Yet because they each received a kinsman-redeemer by God’s gracious Word, they lived. How, then, is Christ our Kinsman-Redeemer? Without Him, we would be dead. Our first parents, Adam and Eve, sold themselves to sin, death, and the devil in the Garden of Eden. Thus, “the wages of sin is death” (Romans 6:23a); death is our lot in this world. And unless we have a Kinsman-Redeemer, we are doomed to eternal death. We have no relative—no human being—to redeem us from this death, which we see quite clearly at the near-sacrifice of Isaac in Genesis 22 (the sacrifice of Isaac would’ve been insufficient).
Therefore, Christ gave Himself over to sin, death, and the devil in the Garden of Gethsemane and bought us back—redeemed us—from the power of this unholy trinity in His death and resurrection. Therefore, “the free gift of God is eternal life in Christ Jesus our Lord” (Romans 6:23b). By becoming human, Christ became our brother (Mark 3:34-35; Romans 8:29; Hebrews 2:11), and being thus perfect God and perfect human, He redeemed us from death.