Tim Hughes penned the tune in 1999 as a response to how he felt after reading the second chapter of St. Paul's letter to the Philippians. More surprisingly, it was also inspired by a Stephen King movie. He explained to Christianity magazine: "I wrote this song when I was studying at university in Sheffield. I'd been reading about the life of Jesus, and about us imitating Christ's humility and the fact that Jesus gave up everything, walked upon the earth and was obedient even to death on a cross, in Philippians 2. So I began as often we do, to worship out of response to that.
I began with these words, 'Light of the world, you stepped down into darkness, I opened my eyes, let me see,' and also I had that tag, 'I would never know how much it cost, to see my sin upon the cross.' But I could never ever finished the chorus, and I got more and more frustrated. When I get to that place, often what I do is park this song and move on.
About six months later I went to the movies to watch a film called The Green Mile, a Stephen King story about substitution; someone taking on a punishment that wasn't rightfully is to take. The themes of the cross and sacrifice was so powerful, and I began to sing this song again. I thought, 'I must finish that,' but again, I couldn't get the chorus.
I began to listen through to old – back then it was cassettes – tapes of melodic ideas I'd had, and I found an old school melodic idea which I thought, 'Actually, that could fit really nicely,' and then quickly wrote those lyrics. The verses speak about what Jesus has done and the chorus needed to be a simple, 'Well, I'm going to respond by worshipping you, bowing down, saying that, you're my God.' So that's how this song came together."
Not everybody spotted the song's potential to be a worship classic. Hughes explained: "What is interesting is I played it to a friend, Matt Redman, who said, 'Oh, you know, what may be you could use the chorus is a little tag thing. I'm not sure of the rest is particularly strong.' So he tried to sabotage the song! I sat on it for about a year and didn't ever use it."
"Then I played it once in a ministry time and Mike Pilavachi, who heads up Soul Survivor, came up to me and said, 'What is that song? You have to sing that song every week for the next year,' which I almost ended up doing. I was really surprised when it took off. As a songwriter, you're not always the best judge of your own work."