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.”
BSB · Berean Standard Bible
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.
KJV · King James Version
then his brother’s wife shall come to him in the presence of the elders, and loose his sandal from off his foot, and spit in his face. She shall answer and say, “So shall it be done to the man who does not build up his brother’s house.”
WEB · World English Bible
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 she shall answer and say, So shall it be done unto the man that doth not build up his brother’s house.
ASV · American Standard Version

Related passages

From the Treasury of Scripture Knowledge, grouped by the word they explain.

loose his shoe
Pulling off the shoe seems to express his being degraded to the situation of slaves, who generally went barefoot; and spitting in or rather before, (biphney) his face, was a mark of the utmost ignominy.
Ruth 4:7, 8; Isaiah 20:2; Mark 1:7; John 1:27
spit
Numbers 12:14; Job 30:10; Isaiah 50:6; Matthew 26:67; Matthew 27:30; Mark 10:34
So shall
Genesis 38:8–10; Ruth 4:10, 11; 1 Samuel 2:30