For certain men have crept in among you unnoticed—ungodly ones who were designated long ago for condemnation. They turn the grace of our God into a license for immorality, and they deny our only Master and Lord, Jesus Christ.
Verse 4. For there are certain men crept in unawares. The apostle now gives a 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." .
Here we have a reason of the foregoing exhortation assigned, why we should contend so earnestly for the Christian faith once delivered by Christ to his apostles, because there were crept, by little and little, such seducers into the church, as would endeavour to adulterate and corrupt it: There are certain men crept in unawares.
For there are certain men crept in unawares,.... 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...