Jude 1:4

“For there are certain men crept in unawares, etc.] These words contain a reason why the doctrine of faith should be contended for, because of false teachers, who are described as being then upon the spot; the Apostles Peter and Paul had foretold that they would come, but Jude here speaks of them as in being; wherefore present rigour and vigilance were necessary to be used: their names are not mentioned, nor their number, only that there were “certain”, or “some men”; which is done to stir up the saints to self-examination, whether they were in the faith; to diligence, in finding out these men; to vigour, in opposing them; and to care, to nip error and heresy in the bud: and they are said to…”

“certain men--implying disparagement. crept in unawares--stealthily and unlawfully. See on Pe2 2:1, "privily shall bring in damnable heresies." before . . . ordained--Greek, "forewritten," namely, in Peter's prophecy Jde 1:17-18; and in Paul's before that, Ti1 4:1; Ti2 3:1; and by implication in the judgments which overtook the apostate angels. The disobedient Israelites, Sodom and Gomorrah, Balaam and Core, and which are written "for an example" (Jde 1:7, and Jde 1:5-6, Jde 1:11). God's eternal character as the Punisher of sin, as set forth in Scripture "of old," is the ground on which such apostate characters are ordained to condemnation. Scripture is the reflection of God's book of life in…”

“For there are certain men crept in unawares - The apostle now gives “reason” for thus defending the truth, to wit, that there were artful and wicked men who had crept into the church, pretending to be religious teachers, but whose doctrines tended to sap the very foundations of truth. The apostle Peter, describing these same persons, says, “who privily shall bring in damnable heresies.” See the notes, 2 Peter 2:1. Substantially the same idea is expressed here by saying that they “had crept in unawares;” that is, they had come in “by stealth;” they had not come by a bold and open avowal of their real sentiments. They professed to teach the Christian religion, when in fact they denied some of…”

“There are certain men crept in, who were of old described before - Even as early as Enoch; of whom it was foretold, that by their wilful sins they would incur this condemnation. Turning the grace of God - Revealed in the gospel. Into lasciviousness - Into an occasion of more abandoned wickedness. Jude 1:5”

“1:4 Abusing God’s marvelous grace by saying that it allows us to live immoral lives is a constant temptation (cp. Rom 6).”

“crept: Mat 13:25; Act 15:24; Gal 2:4; Eph 4:14; Ti2 3:6; Pe2 2:1, Pe2 2:2 who: Rom 9:21, Rom 9:22; Pe1 2:8; Pe2 2:3 ungodly: Jde 1:15; Sa2 22:5; Psa 1:1; Pe1 4:18; Pe2 2:5, Pe2 2:6, Pe2 3:7 turning: Rom 6:1, Rom 6:2; Gal 5:13; Tit 2:11, Tit 2:12; Heb 12:15, Heb 12:16; Pe1 2:16; Pe2 2:10, Pe2 2:18-22 denying: Tit 1:15, Tit 1:16; Pe2 2:1; Jo1 2:22 only: Psa 62:2; Joh 17:3; Ti1 6:15, Ti1 6:16; Rev 15:4 Jude 1:5”