For certain intruders have stolen in among you, people who long ago were designated for this condemnation as ungodly, who pervert the grace of our God into licentiousness and deny our only Master and Lord, Jesus Christ.
Jude 1:4 (NRSV)
It is not grace, but rather a distorted understanding of grace if you use it to do things that you shouldn't be doing. Anyone who uses grace to excuse inappropriate behaviour, or to excuse wrongdoings perverts the gospel.
The Apostle Jude cautions us to be wary of so-called believers who exploit God's grace as an excuse to live an unholy life. Aselgeia, which is the Greek term for "licentiousness," means “unbridled self-indulgence; to contaminate what is clean or pure”. Here Jude describes how these believers flagrantly twisted the gospel of God’s grace out of context to indulge in their sinful living.
Grace is undoubtedly on the side of sinners (that’s the good news!). However, grace is never extended to us so that we can continue to sin (if it’s true, then the good news is actually bad news because it condones sin!).
Grace rests on Jesus.
Anything (that we think or do) that is at odds with His identity or nature cannot be said to be of grace. Jesus' unearned gift of grace is not a "sin haven" for us to keep pursuing a self-indulging life, but rather a freedom to live as true sons and daughters of God.
If we ever assume grace allows us to be less than who we are in Christ, then we are saying that grace is an obstacle to holy living (and this sort of thinking does not conform with the truth of the gospel). This will make us dreadfully apathetic in our walk with God.
A careful reading of the gospel reveals that genuine grace transforms our thinking and conduct. Grace had a profound impact on many of Jesus' followers, including Peter, John, Mary Magdalene, Zacchaeus, and Paul. Now, we are aware that these people do have their faults and sinful shortcomings, but unlike the so-called believers Jude outlined, they never used grace to explain away their failings or to justify their sins; rather, they saw grace as a means out of a life of sin.
If you sincerely believe and act in accordance with these early Christians' understanding of God's grace, there is no limit to what you can accomplish for God's glory.