The Greek word used by Jude refers to the inner garment worn underneath all other clothing. With this phrase, he likely has fleshly desire in mind, similar to Paul’s use of the term. He envisions sexual immorality as staining this garment and so warns the church not to be taken in with their way of life but to hate sin. Coming close to those who have fallen to the false teachers is dangerous and could ensnare some. Thus there is the need to detest these sinful acts (see also John 3:20; Hebrews 1:9; Revelation 2:6).1
23 save others by snatching them out of the fire; to others show mercy with fear, hating even the garment stained by the flesh.