If he could do it, the devil would lure us from the straight and narrow path a mile at a time. If not by a mile then by a yard or a foot. But Satan knows that he cannot expect us to leap from a righteous life into the depths of depravity in one sudden decision, so in most cases his enticements will be so subtle, so unnoticeable, that he may only gain an inch at a time. ‘It’s only a little sin,’ he mocks. 'What can such a tiny indiscretion hurt? It’s harmless. Enjoy yourself. This is not important enough to deny yourself. Go ahead and try it this once.’ But through repetition of our sings those tiny inches soon add up to miles as we drift gradually into more serious sins.
— Putting on the Armor of God, page 95, “Gradual temptations”