The iconic hymn "Amazing Grace" has been sung in churches, funerals, and major public events across the United States and around the world. The story on how it was written has now become the focus of a musical play in Broadway.

According to Michelle Miller of CBS News, former police officer Christopher Smith is the writer behind a new Broadway show Amazing Grace Musical that portrays the story of how "Amazing Grace" was made. As a fan of history, he originally read about the story behind the hymn back in 1997.

"I was literally wandering through a library and pulled a book off a shelf at random," Smith said.

Miller reported that the book Smith selected was about a British slave trader in the 1700s named John Newton, who later was held captive in West Africa after years of selling slaves to America. While Newton managed to escape captivity, he almost died at sea.

"He lived through a hurricane on a sailing vessel and it was during the dark night he finally cries out and says, 'God, have great mercy,'" Smith said. "That was the beginning of a great journey."

According to CBS News, Newton survived and later converted to Christianity. He then became an abolitionist and wrote the lyrics behind "Amazing Grace."

"It crosses cultural boundaries, age boundaries, it crosses time itself and this man's story is the root of it," Smith said of the hymn's impact.

Smith added that "Amazing Grace" was one of the few songs American society can agree on as a culture, referencing how President Barack Obama sang the hymn during the eulogy for Rev. Clementa Pinckney, who died in the shooting of a historically black church in Charleston, S.C.

"To hear the President of the United States sing that song, it just really validated for me that this was our time, that this was meant to be," Smith said.

Deborah Evans Price of Billboard wrote about the Broadway show, which started playing July 16 at the Nederlander Theater in New York. She noted that the hymn by itself "is a cultural touchstone that often surfaces during trying times."

"Josh Young, Erin Mackey and Tony Award-winner Chuck Cooper star in the musical, with music and lyrics by Christopher Smith, and book by Smith and Arthur Giron," Price wrote. "The play chronicles the life of John Newton, the slave trader turned abolitionist, who wrote the hymn."

Smith elaborated on the journey of making Newton's story into a Broadway musical.

"I had never even heard of him, and it just changed my life," Smith said of finding a library book about Newton's life. "I knew that whatever else I was going to do with my life, I needed to find a way to tell this story."

Smith told Billboard that audiences would connect with Newton's story of struggle and redemption.

"There's something within the human heart that we want to be loved in spite of ourselves," Smith said. "We want to know that we can go back, that we can change. There's not a whole lot in our culture that seems to support that message yet it's a very deep yearning inside people and I realized that John Newton could be a great portrait of that."

According to Smith, Broadway was an excellent location to provide a framework for that portrait.

"Musical theatre is the most immediate entertainment in the world and I wanted people to see it," Smith said. "I want people to see real tears and hear real laughter. When people get into fist fights I want to hear those punches landing."

Billboard reported that Smith spent ten years writing the musical in Philadelphia. He met with producer Carolyn Rossi Copeland, the founder of Lamb's Theatre Co. in Times Square, and tried to convince her of the play's potential.

"She wasn't completely convinced right off the bat but my investors in Bucks County never wavered," Smith said in reference to how he developed and pitched the play. "I set up an organization with them so that if I succeeded, they succeeded. If I failed, they failed. So we were really in it together from the start."

According to Billboard, Smith later hired Copeland as a producer. She, alongside 82-year-old manufacturer Alexander Rankin, raised $16.4 million to bring the show to New York City.

"It's not a message for just one theatre and one town," Smith said.

Smith observed the audience reaction to the show's previews, which looked encouraging to him. He thought it was "an incredible experience for everybody there."

"The audience watches the show and I watch the audience," Smith said. "They are coming out singing. They are coming out crying and they are all standing up with us at the end and singing 'Amazing Grace.' I've never seen anything like 1,200 people on 41st Street in the heart of New York standing and singing 'Amazing Grace.'"

Smith contended that even though the play had distinct Christian themes, audience members of all faiths can still resonate with the play's message.

"We put it together in such a way that people walk in with absolutely no faith tradition whatsoever -- and have no idea of who John Newton is -- and we give them a great journey that they can relate to," Smith said. "For people like myself, there's obviously a much bigger dimension, a spiritual dimension. For other people, it's just a great journey and that's what it should be."

Tickets can be purchased at Amazing Grace Musical's website.