Deuteronomy 25:9
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. (Deuteronomy 25:9)
So shall it be done.
 The only exceptions were the high priest, who was not subject to the levirate law (Lev. 21:13, 14), brothers living at a distance, and the aged.
In his face.
 Jewish commentators usually interpret this as spitting on the ground “before his face.” This seems reasonable, because the preposition is not “upon,” but “by” or “before” (Deut. 11:25; Joshua 10:8). Spitting before the face was thought to be humiliating (Num. 12:14). This verb appears three times in the Hebrew Bible.
Loose his shoe.
 Literally, his “sandal.” Jewish tradition indicates the shoe of the right foot. The deed here described was regarded as an act of indignity, inasmuch as failure to comply with the levirate law (see on v. 5) was looked upon as a mark of selfishness (see Ruth 4:6). The placing of the shod foot on property proclaimed either one’s contempt for it or one’s rightful ownership over it (Ps. 60:8; 108:9). Accordingly, the removal of the man’s shoe by his brother’s widow proclaimed the man’s unworthiness. He refused to do what was rightfully to be expected of him. Compare S. of Sol. 7:1 for the figure of the sandaled foot as a picture of beauty and desirableness. To go unshod was looked upon as degrading (2 Sam. 15:30; Isa. 20:2, 4) or as a token of humility (Ex. 3:5; Joshua 5:15).