The phrase snatching them out of the fire
seems to echo Zechariah 3:2 (also found in Amos 4:11). The fire from which deliverance is to be sought is the final judgment. This implies that some in the Christian community had succumbed to the persuasion of the heretics and had themselves become liable to the judgment about which Jude has warned throughout his epistle. He is calling the church to forceful and swift action to rescue those who have come under the sway of the heretics’ teaching.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.