Now in former times in Israel, concerning the redemption or exchange of property, to make any matter legally binding a man would remove his sandal and give it to the other party, and this was a confirmation in Israel.

Deuteronomy 25:8
Then the elders of his city shall summon him and speak with him. If he persists and says, "I do not want to marry her,"

Deuteronomy 25:9
his brother's widow shall go up to him in the presence of the elders, remove his sandal, spit in his face, and declare, "This is what is done to the man who will not maintain his brother's line."

Ruth 4:8
So the kinsman-redeemer removed his sandal and said to Boaz, "Buy it for yourself."

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 neighbor: and this was a testimony in Israel.