Moral failure comes not from enormous misdeeds, but through lapses in "tremendous trifles."

Have you ever tried quickly to pull a dangling thread from the hem of a pant-leg or skirt or jacket, only to find you've got hold of one of those dreaded running stitches? Instead of breaking off, the thread continues to unstitch itself until the entire hem falls out. Instead of freeing yourself from one annoying little thread, you now have a major clothing catastrophe.

It is always the little things that end up getting us in the biggest trouble. G. K. Chesterton referred to these as "tremendous trifles." Life, Chesterton observed, does not usually present us with big temptations or grandiose sins. Instead, we constantly encounter little temptations that can easily slip under the threshold of our …