Tim Keller, told the following story about a man named Hasheem Garrett, who learned the art of forgiveness. Hashim was a 15-year-old, living with his mother and hanging out on the streets of Brooklyn with a gang, when he was shot six times and was left paralyzed from the waist down.

For most of the next year he lay in a New York City hospital, fantasizing about revenge. He later wrote: “Revenge consumes me. All I could think about was, just wait, till I get better; just wait till I see this kid.”

But when he was lying on the sidewalk immediately after his shooting, he had instinctively called out to God for help, and, to his surprise, he had felt this strange tranquility. Now during his rehabilitation, a new thought, struck him, namely, that if he took revenge on this kid, why should God not pay him back for all his sins? He concluded, “I shot a kid for no reason, except that a friend told me to do it, and I wanted to prove how tough I was. Six months later, I am shot by somebody because his friend told him to do it.”

That thought was electrifying … He could not feel superior to the perpetrator. They were both fellow sinners who deserved a punishment—and needed forgiveness.

Hasheem said, “In the end I decided to forgive. I felt God had saved my life for a reason, and then I had better fulfill that purpose … And I knew I could never go back out there and harm someone. I was done with that mindset and the life that goes with it … I came to see that I had to let go and stop hating.”