Ephesians 2:8-10 and Titus 2:11-14 describes how the grace of God makes change inevitable. When the person is saved by grace, they have that desire to serve Christ and they love to serve Christ. They do not do out because they have to but because they want to. They do good works no longer under the law but fulfilling the Law by faith (Romans 3:31). The very grace of God makes people serve Christ willingly out of a loving heart. That is what is meant that salvation is by faith alone but never by a faith that is alone. If you are truly saved then there thought to be a change from sinful lifestyes to growing up in grace in the Lord Jesus Christ. Alone, Christians have no power over sin but it is by the grace of God they have that power against sin.
1 Corinthians 6:9-11 declares the very change brought in the lives of people who lived sinfully. The very sting started, "Know ye not that the unrighteous shall not inherit the Kingdom of God?" Romans 3:10-19 shows we are not righteous. The proof of man's being unsaved is not only evident in self-righteousness but a wicked lifestyle. What is disturbing is that many people think they are "good" even if they love to live a life of sin. Many religious but lost people are faithful to their religion but are also degenerate in their lifestyles at the same time. When people are truly saved, they are delivered from their sinful lifestyles by the grace of God so nobody can boast.