The Christians addressed in Jude were under attack; it was an attack on holy living. The false teachers were saying that one could be considered godly while living an ungodly life. By their teachings and conduct they were trying to turn,
…the grace of our God into lewdness and deny the only Lord God and our Lord Jesus Christ. (v.4)
They were saying that, because of God’s grace, a person could sin all they wanted to and still be forgiven. The apostle Paul addressed this kind of thought directly when he wrote:
What shall we say then? Shall we continue in sin that grace may abound? Certainly not! How shall we who died to sin live any longer in it? (Romans 6:1-2 NKJV)
When we have an intimate relationship with the God of the universe, made possible by Jesus’ death on the cross, there must be a change in the way we live our lives. It can be no other way.
Although we may not immediately be free from all the sinful habits we have acquired before salvation, once we have given our lives to Christ there should be a noticeable change in what we do, what we want to do, and how we think. We should want to please God in our behavior out of the love and gratitude we have for Him because He saved us.
Our attitude towards sin should change; we should begin to hate it, to be sickened by it. We should want to be free from its power. The absence of this change should give us cause to question the reality of our salvation.
The apostle John spent much of his first epistle addressing the connection between our actions and our spiritual condition. He said that one who is truly a follower of Jesus will not continue in willful, habitual sin (1 John 3:6). Nowhere in the Bible does it lead one to believe that it is possible to obey God and continue in a lifestyle of unrepentant sin.
The problem in Jude was not an instance of one interpretation or opinion being discussed between groups of born again believers. This was an attack on essential Gospel doctrine.