Jude, brother to James, writes this one chapter book about “our common salvation”. Common, meaning that there are certain core principles to this faith that stand once and for all. Thus he reminds “the called” to contend earnestly for the faith. Why? Then as now, many have tried to change, distort or add to the tenets of our apostolic faith. The issue decried by Jude in theses verses is the most common place that “innovators” start, namely, works righteousness and licentiousness. Cultists can not believe/allow God’s amazing grace to stand on its own. They say either “you need to add to it” or in this case turn God’s grace into a cause for “licentiousness” or “anything goes…the bigger the sin the bigger the forgiveness”. God’s grace given to us by God through faith in Jesus is all sufficient, we can’t add to it and our new life in Christ does not allow us to continue in purposeful sin. See also Ephesians 2:8-10 and Romans 6:1-7.