“A fundamental insight of Martin Luther’s was that ‘religion’ is the default mode of the human heart. Your computer operates automatically in a default mode unless you deliberately tell it to do something else. So Luther says that even after you are converted by the gospel your heart will go back to operating on other principles unless you deliberately, repeatedly set it to gospel-mode. We habitually and instinctively look to other things besides God and his grace as our justification, hope, significance, and security.”[i]—Timothy Keller, The Prodigal God: Recovering the Heart of the Christian Faith
[i] Timothy Keller, The Prodigal God: Recovering the Heart of the Christian Faith (New York: Riverhead, 2008), 128–29.