The Bible tells us a lot about the new birth. The apostle Paul tells us that if anyone is in Christ, is a new creation, old things has passed away and all things has become new. Jesus also speaks to Nicodemus telling him that it is necessary to be born again. To be born again is to become a new person, casting aside what we were before and immersing ourselves in the will of God.
We who are in Christ are no longer the same people, so I have always held the idea that the only place where we can be transformed from the worst person to a different person is in the arms of our beloved and King Jesus Christ.
Clearly the Bible does not tell us about this without presenting the evidence, because we have the life of the apostle Paul, who first was a persecutor of the church and became the greatest writer of the new testament. On the other hand we have Peter, who denied Christ three times and cut off the ear of a roman soldier, however, he became the great apostle of the early church. And so we have many cases in the Bible of men who were transformed by the power of God and today we have as evidence our own life, which Christ has changed overwhelmingly and we give glory to God for it.