By being vigilant you discover an enemy approaching the door of your heart, for example, the temptation to think an evil thought of a fellow man. Immediately your will to resist is awaked and you thrust out the temptation, but at the very next moment you sustain a setback in the form of a self-satisfied thought: My, but I was alert! Your apparent victory became a horrible defeat. Humility was missing.
"Way of the Ascetics"