I’ve recently begun reading John Piper’s book When I Don’t Desire God. It’s one of those books that I’ve had for quite a while and am just now getting around to reading it. If you are interested, the entire book is available to download for free at Desiring God’s website.
In chapter 1 there was a quote from C.S. Lewis regarding the role of duty. Most of us at times struggle with the role of duty. We may not want to read our Bibles because we feel it is a duty instead of a delight. So, we tell ourselves to wait until it feels like a delight. Lewis compares the idea of duty to a crutch which we all must use sometimes to help us.
Provided the things is in itself right, the more one likes it and the less one has to “try to be good,” the better. A perfect man would never act from a sense of duty; he’d always want the right thing more than the wrong one. Duty is only a substitute for love (of God and of other people), like a crutch, which is a substitute for a leg. Most of us need the crutch at times; but of course it’s idiotic to use the crutch when our own legs (our own loves, tastes, habits, etc.) can do the journey on their own! ~ C.S. Lewis (quoted in When I Don’t Desire God, p. 18)