American swimmer Michael Phelps wowed the whole world after bagging his record 23rd Olympic gold medal at the Olympic games in Rio De Janeiro on Aug. 13, and even "The Purpose Driven Life" author Rick Warren was impressed.

The Saddleback Church pastor even posted Phelps' photo on his Facebook page and wrote wonderful things for him. "Saw Michael Phelps, #PurposeDrivenSwimmer, win his 23rd gold! I've prayed for you each day in Rio. God has a great future for you," says Warren.

Warren's encouraging words could just be what Phelps needs in his spiritual journey. In the past, Phelps faced controversies. He was arrested for driving under the influence in Salisbury, Maryland way back in November 2004, and he pleaded guilty to driving while impaired.

Then in February 2009, a photo of him using a bong lost him his Kellogg Company endorsement, and he was even slapped with a three-month suspension by USA Swimming, the national governing body for competitive swimming in the United States. His eyebrow-raising controversies did not end there. In September 2014, Phelps committed the same mistake of driving under the influence in Baltimore, Maryland.

It was only after he read "The Purpose Driven Life," Warren's bestselling book, that his life changed for the better. He told ESPN that NFL star Ray Lewis urged him to check into Meadows, a behavioural rehab facility outside Phoenix. Once he got admitted, Lewis gave him Warren's book.

"I was a train wreck," Phelps recalled. "I was like a time bomb, waiting to go off. I had no self-esteem, no self worth. There were times where I didn't want to be here. It was not good. I felt lost."

The book proclaiming God's love shed light on Phelps' life. He said the book "turned me into believing there is a power greater than myself and there is a purpose for me on this planet," and he could not thank Lewis enough for saving his life.