Bestselling author and atheist turned Christian Lee Strobel is sharing his own experience of God's healing power in his new book, entitled A Case for Grace, in which he explores the lives of Christians whose lives were transformed by God.

In a post, Strobel shared the time when he was found unconscious by his wife on their bedroom floor. Unknown to him and his family, he was suffering from a condition called hyponatremia, and his blood level was plummeting to the point where it became life threatening.

The condition, he said was causing water to enter into his cells, triggering swelling in the brain and causing him to have hallucinations. He said he imagined going to hell, seeing monsters in his periphery, his wife leaving him and his children disowning him.

"From my perspective, this was no medically induced fantasy; this was indistinguishable from reality. I felt the full emotional impact of every part of it. I have never been homeless, but in my mind I experienced what it's like to be. I have never been broke, abandoned or ostracised, but now I knew what those feel like. I have never been imprisoned, but now I could understand the dehumanising effects of incarceration."

When he woke up in the hospital, it led to the discovery of a slew of medical conditions that could have killed him, including complications stemming from a routine heart procedure affecting his kidneys, pneumonia in his lungs and a severe allergic reaction to medication for his voice problem - all of which were not known to his doctors before.

"I remember awakening in a hospital emergency room, a physician looking down at me. 'You're one step away from a coma,' he said, 'and two steps away from dying,'" Strobel said.

In an  interview with The Christian Post, Strobel shared that his new book is about experiencing God and how lives can be changed by Him.

"In and of itself it's not sufficient to prove the case for Christianity, but it's an important part of the case because if God exists, if Christianity is true, then you would expect that lives would be changed. So this is a book about God changing lives in unexpected and radical ways," he said.

Strobel said that in order to illustrate different aspects of God's grace, he travelled 20,000 miles to sit down and interview people to understand the role God played in their lives.

"In my book, in the story of a guy who kills 17,000 people, [I ask] can God forgive him? And also how to give grace to yourself. Even if we feel God has forgiven us, how do we come to the point where we feel that we've forgiven ourselves. So there's different aspects of grace that are talked about in the book. Each illustrated with [people] we have interviewed," he said.