Truly believing something changes our behavior. The issue some people get confused about is which comes first: works before salvation or salvation before works? Good works follow as a result of true belief. Yet grace still comes first. “Mercy understood is holiness desired. … Grace fosters an eagerness for good. Grace doesn’t spawn a desire to sin. If one has truly embraced God’s gift, he will not mock it” (Max Lucado, In The Grip of Grace [Dallas, TX: Word Publishing, 1996], 82). Yes, true faith is proven by a changed life. But the changed life isn’t the way to get in a right relationship with God. Grace through faith in what Jesus did on the cross for us is how we are made right with God once in for all.
The thief who recognized Jesus as God’s Son did not have an opportunity to do anything except believe. He couldn’t get baptized, take communion, tithe, share the gospel, or perform any other religious act as proof of his faith. He is a great example of how grace through faith alone is the basis for salvation. “But if it is by grace, it is no longer on the basis of works, otherwise grace is no longer grace” (Romans 11:6 NASB). If you have been trying to clean yourself up before presenting your life to God, give up now. You can’t do it. And you don’t need to. Grace is a free gift. Just receive it and let God clean up your life.
Source: https://www.amazon.com/Grip-Grace-Max-Lucado/dp/0849937264