What does Ruth 4:3 mean?
The issue of land ownership in the Old Testament is closely tied to Israel's relationship with their God.After Abraham's father died, God called Abraham to leave Haran and travel to Canaan. God promised that one day Abraham's descendants would own all of Canaan (Genesis 12:1–2; 15:18–21). God's promise to Abraham was unconditional; at some point, His descendants would inhabit specific boundaries. After God rescued the Israelites from Egypt, He explained how that generation could acquire and keep Abraham's inheritance: if they obeyed God's Law and served Him only, they would receive the land and keep it, enjoying the abundance God would provide. If they rejected Him, they would experience famine, pestilence, and exile (Deuteronomy 28).
The division of that land by tribe, clan, and family takes up much of the book of Joshua. Joshua started the process of driving the Canaanites out, and the battles continued through the reign of David. For instance, at the time of Ruth, the Israelites have Bethlehem, but the Jebusites control nearby Jerusalem.
Land ownership was an extremely important part of Israelite life. It was the inheritance of God and proof that one's family was in obedience to God. When Elimelech left Bethlehem, he would have sold his land to get capital for his move to Moab. Some biblical scholars think God killed Elimelech as punishment for forsaking his family's birthright. The book doesn't say. When Naomi returns to Bethlehem without husband or sons, she might feel she has dishonored her husband by not providing him with an heir who can buy back the land (Ruth 1:11–13, 20–21). She certainly feels abandoned by God (Ruth 1:20–21).
Even if Naomi had the money to buy back the land, widows did not own land; they needed a husband, son, or another male relative to own it and use the proceeds to support them. Naomi doesn't even have the money to buy seed or hire laborers. Only once does the Old Testament speak of daughters inheriting their father's land: the daughters of Zelophehad had no brothers but insisted their father had the right to pass on his land to them. The leadership agreed, so long as they married within their tribe, keeping the land in the tribe (Numbers 36).
To stabilize land ownership, God codified the tradition of the kinsman-redeemer into the Mosaic law. If a man fell into debt and had to sell his land to survive, a relative would buy it and either sell it back to the man or return it at the year of Jubilee (Leviticus 25:25–28, 47–49). This is part of Ruth's plan for providing for Naomi. She wants Boaz to redeem the land from Elimelech's buyer and provide Naomi with an heir who will inherit it back in Elimelech's name. This is a big ask, but Boaz is more concerned with how God's heart is expressed through the spirit of the Law. So, he boldly approaches Elimelech's nearest relation and challenges him to buy "Naomi's" land.
The man quickly agrees (Ruth 4:4). Because Naomi has no male heir, he will not have to hand it over at the year of Jubilee. He will gain more land for his own sons. But then Boaz reveals the rest of Ruth's plan (Ruth 4:5). He tells the man he must marry Ruth and give Naomi an heir. The man withdraws (Ruth 4:6). To spend the money to buy the land just to give it to a child born to another man's name would incur financial difficulties unless his own land was unusually prosperous, which is in question considering the recent famine.
"Relative" can mean male relative or brother. He's most likely not Elimelech's brother; if he were, his refusal to marry Ruth would be a great dishonor (Deuteronomy 25:7–10). Legally, he could buy the land and not marry Ruth, but Boaz has challenged him in front of the city elders and several other witnesses. In an honor/shame culture, it's enough to make the man politely back out.