“And when he had come to Jerusalem, he attempted to join the disciples. And they were afraid of him, for they did not believe that he was a disciple. But Barnabas took him and brought him to the disciples and declared to them how on the road he had seen the Lord, who spoke to him, and how at Damascus he had preached boldly in the name of Jesus” (Acts 9:26-27).
I have a friend across town who was in prison for 10 years, and has been back in society for the same amount of time. He married a woman I know, supports her well with his considerable Oholiab and Bezalal-quality construction gifts, and loves her children as his own. He serves the church, helps the needy, confesses sin easily, gives glory to God in every conversation, belongs to a Saturday morning men’s prayer group—and is regularly shunned by a segment of people who continue to not accept him nor believe he is a new man in Christ.
When my friend first moved into the neighborhood, fliers appeared in everyone’s mailbox announcing the presence of a felon on their streets. In fact, this happened twice. He was alarmed and did not know what would come of it but continued doing what he was doing and being courteous to his neighbors. Still, the past blows up in his face unexpectedly now and then, like an Afghan road studded with IEDs. I have seen people reject him even as he has fixed their computers and lent them his propane grill for a cookout.
Two thousand years ago a murderer named Saul became an apostle named Paul, by the grace of God. The verses above indicate that not everybody believed he was a changed man, and they were afraid to take him into their circles. So what did his first Christian friend Barnabas do? How did he prove that Saul was safe? He did it in a very down-to-earth way. He did not wax philosophical or theological but instead reported on what Paul had been up to. First of all, Paul had seen the Lord and heard His voice on his way to a real town named Damascus, which was verified by witnesses. But if you don’t believe that, then consider he had been preaching boldly in the name of Jesus ever since that day.
If you are not sure about someone’s conversion, do not speculate based on psychological theories of change, which all contradict each other anyway and have no light in them. Observe what the person does and what he says, for this is the way God bids us to know a man. And as Paul said, “No one can say ‘Jesus is Lord’ except in the Holy Spirit.”