Verse 1 False prophets also; that is, in ancient times, when the true prophets, referred to in the 2 Peter 2:1, made their predictions. For various allusions to these false prophets, see Jer. 28:15-17. Ezek. 13: 22:22, 25, 28.--Privily; privately, by stealth.--Damnable heresies; that is, heresies fatal to the welfare of the soul.--Denying the Lord; denying him as their Lord and Master.
Verse 2 Many shall follow, &c. Men never have so great a power and influence for evil, as when they introduce immoralities and sin under the cloak and defence of some perverted form of religious doctrine. This is fanatical vice, the worst, most corrupting, and most dangerous form in which vice ever appears,--as the history of Christianity in all ages will testify. It is on, this account that heresy is denounced in the New Testament in such strong terms of reprobation. For heresy is not honest error. It is the hypocritical perversion of religious truth to the purposes of licentiousness and sin.--The way of truth; true religion.
Verse 3 Feigned words; artful and hypocritical pretences.--Make merchandise of you. Judas made merchandise of his Master, betraying and sacrificing him to promote his own ends. So it is said these men should sacrifice the cause of Christ to their own selfish purposes.--Whose judgment now, &c.; that is, whose judgment and condemnation shall come upon them soon and suddenly.
Verse 4 The angels that sinned. Another allusion to angels, as having rebelled against God, and incurred his terrible retribution, is found in Jude 1:6.
Verse 5 The old world; the world before the flood.--Noah the eighth person; that is, Noah with seven others. Noah was a preacher of righteousness, inasmuch as he set an example of obedience, and made efforts, in various ways, to warn and to save his generation. (Hebrews 11:7.)
Verse 7 Filthy conversation; corrupt and wicked conduct.
Verse 8 Vexed his righteous soul; felt perpetually displeased and troubled.
Verse 9 The Lord knoweth, &c. This is the inference from what precedes. That is, if the Lord spared not the rebel angels, nor the old world, nor the cities of Sodom and Gomorrah, but brought terrible judgments upon them for their sins, while he saved Noah and his family, and Lot,--then the Christian might be assured that he would still continue to protect the good and condemn the wicked.
Verse 10 To speak evil of dignities; of authority and power above them, which they ought to regard with respect and submission. The meaning is, that they are restive and rebellious against all authority.