"The opponents’ ethical practice, in which sexual immorality seems prominent, is plausibly seen as an accommodation to the permissiveness of pagan society, a perennial temptation in the early church, especially when Christian morality impeded participation in the social life of the cities. The false teachers may therefore be seen as aiming to disencumber Christianity of its eschatology and its ethical rigorism, which seemed to them an embarrassment in their cultural environment, especially after the evident failure of the Parousia expectation. From a general familiarity with Hellenistic religious debate they were able to deploy current skeptical arguments about eschatology and divine revelation. Perhaps they saw themselves as rather daring young radicals trying to clear a lot of traditional nonsense out of the church. Whether they also had any positive religious teaching our evidence does not allow us to say. The analogy with radicals in other generations suggests that a largely negative message could have sounded impressive enough (cf. 2:18a)."
Richard J. Bauckham, Jude, 2 Peter (WBC 50; Waco: Word Books, 1983), 156.
"They have abandoned Christian morality and embraced sexual immorality (2:2, 10, 14, 18), giving themselves over to the inordinate satisfaction of their desires, including drunkenness and gluttony (2:13). They engage in self-indulgent behavior and revelry in the context of the common banquet of the Christians. Although they promise “freedom” (2:19), they are people who live without moral law and are not subject to the divine command (2:21; 3:17). In truth, they are nothing more than “slaves of corruption” (2:19). One of their principal motivations is avarice (2:3, 14), viewing others as a means of gain, people to be exploited for their own ends. The heretics are arrogant in their denial of the Lord and their slander of celestial beings (2:2, 10, 12, 18), a trait especially evident in their strident skepticism (3:3–4)...
"The error of the heretics is doctrinal and not only moral. Peter calls them “false teachers,” who have tried to introduce “heresies of destruction” into the congregations (2:1) by using deceptive means (2:3). At the heart of the error is their skepticism regarding the coming of the Lord and the divine judgment on the day of the Lord (3:3–10). Their argument is that future judgment will never occur, and they rest their case on the apparent delay in the Lord’s advent (3:4, 9; cf. 2:3). They criticize the apostolic preaching regarding the coming as an invention of the preachers themselves and tag their proclamation as nothing more than “myth.” They even place prophetic inspiration in doubt, claiming that the prophets spoke of their own accord and incorrectly interpreted their own visions (1:20–21). This eschatological skepticism translates into an affirmation of liberty that throws off moral restraint (2:19; 3:3–4). Moreover, the heretics have sought support in Paul’s Letters, whose message they have twisted (3:15–16). The doctrinal and moral errors of the false teachers are joined at the hip. In fact, at the head of his denunciation Peter declares that the heresy is a denial of the Lord, who has bought them (2:1). At the heart of this denial is the rejection of his sovereignty over their moral lives (2:10).
"The false teachers are members of the Christian communities among whom they promote their error...
"The differences between the situations presented in Jude and 2 Peter argue against identifying the opponents as the same in both letters. The root of the moral problem that Jude combats is a perversion of the doctrine of grace (v. 4). On the other hand, the doctrinal error that is the foundation for the immorality of the opponents in 2 Peter is the negation of the parousia of Christ and future judgment (3:3–10)."
Gene L. Green, Jude and 2 Peter (BECNT; Grand Rapids, MI: Baker Academic, 2008), 151–153.
