This is an excerpt from the 50 frequently asked questions section of The Billy Graham Training Center Bible:
Billy Graham has said, “Christian conversion is the transformation which we experience when we are born of God. Since one is not born over and over again, we must think of Christian development in two phases: birth and growth. A child, for example, is born once. True, he falls down many times, but when he falls he doesn’t need to be born again. His falls, his bumps and bruises are all part of growing. So it is in the Christian life. Birth is sudden, once and for all, but development is the work of an entire lifetime. We can be converted in a moment: the precise moment that we accept Christ. But it takes a lot of prayer, Bible reading, churchgoing, and Christian service to make a mature Christian.”
The Bible says, “My little children, these things I write to you, so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous” (1 John 2:1). “If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness” (1 John 1:9).