Jude 1:23

Sixth, Jude gave instruction concerning those believers who have already fallen under God’s discipline by capitulating to false teachers. We should attempt to extract them from their error before their consequent judgment falls (cf. Amos 4:11; Zechariah 3:2). Fire is symbolic of God’s judgment in Scripture. Here Jude saw God’s judgment coming on believers for yielding to sin or false teaching. [Note: Hiebert, Second Peter . . ., p. 290; Lawlor, p. 127. Cf. John 15:6; 1 Corinthians 3:15.] And he also saw it coming on unbelievers. [Note: Coder, p. 116. Cf. Revelation 20:15.]

In the case of those whom heresy has completely swept away, we should have pity on them rather than condemning them without compassion. Moreover we should regard them with fear, not fear of being infected by physical contact with them, but fear of falling under God’s displeasure and discipline if we embrace their error. We should avoid any contact with these people because of the corrupting influence they can have on us through their words and actions (cf. 1 Corinthians 5:9-11; 2 Thessalonians 3:14-15). The "garment" stands for those things affected by contact with fleshly behavior such as personal habits and practices, speech, companions, and the like. Scripture often uses garments as a symbol of what other people see, namely, our conduct.