Ruth 4:1-4
Then went Boaz up to the gate, and sat him down there: and, behold, the kinsman of whom Boaz spake came by; unto whom he said, Ho, such a one! turn aside, sit down here... And he took ten men of the elders of the city, and said, Sit ye down here. And they sat down. And he said unto the kinsman, Naomi... selleth a parcel of land, which was our brother Elimelech's: And I thought to advertise thee, saying, Buy it before the inhabitants, and before the elders of my people...
Deuteronomy 16:18
Judges and officers shalt thou make thee in all thy gates, which the Lord thy God giveth thee, throughout thy tribes: and they shall judge the people with just judgment.
Boaz sets up a formal public court room at the city gate to settle the estate. By empaneling a legal quorum of ten city elders, he ensures that the real estate transaction and the accompanying family declarations are properly witnessed, recorded, and validated according to municipal code.
Ruth 4:5-6
Then said Boaz, What day thou buyest the field of the hand of Naomi, thou must buy it also of Ruth the Moabitess, the wife of the dead, to raise up the name of the dead upon his inheritance. And the kinsman said, I cannot redeem it for myself, lest I mar mine own inheritance: redeem thou my right to thyself; for I cannot redeem it.
Deuteronomy 25:5-6
If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not marry without unto a stranger: her husband's brother shall go in unto her, and take her to him to wife... And it shall be, that the firstborn which she beareth shall succeed in the name of his dead brother, that his name be not blotted out of Israel.
Boaz binds the purchase of Elimelech's real estate directly to a levirate marriage obligation involving Ruth. The primary legal heir refuses the option because managing both the financial cost of the property and the legal preservation of a dead relative's lineage would dilute his own family's financial estate, forcing him to formally waive his priority right.
Ruth 4:7-8
Now this was the manner in former time in Israel concerning redeeming and concerning changing, for to confirm all things; a man plucked off his shoe, and gave it to his neighbour: and this was a testimony in Israel. Therefore the kinsman said unto Boaz, Buy it for thee. So he drew off his shoe.
Deuteronomy 25:7-9
And if the man like not to take his brother's wife, then let his brother's wife go up to the gate unto the elders... Then shall his brother's wife come unto him in the presence of the elders, and loose his shoe from off his foot, and spit in his face, and shall answer and say, So shall it be done unto that man that will not build up his brother's house.
To formalize the waiver of his redemption rights, the primary relative removes his shoe and hands it to Boaz. While this modifies the punitive form of the Deuteronomy ritual (omitting the public spitting because the relative willingly cooperated with Boaz rather than aggressively refusing family duties), the extraction of the footwear serves as the binding, permanent sign of property transfer and contract finalization.