All vices when overcome grow feeble, and when beaten are day by day rendered weaker, and both in regard to place and time grow less and subside, or at any rate, as they are unlike the opposite virtues, are more easily shunned and avoided: but this one when it is beaten rises again keener than ever for the struggle; and when we think that it is destroyed, it revives again, the stronger for its death. The other kinds of vices usually only attack those whom they have overcome in the conflict; but this one pursues its victors only the more keenly; and the more thoroughly it has been resisted, so much the more vigorously does it attack the man who is elated by his victory over it. And herein lies the crafty cunning of our adversary, namely, in the fact that, where he cannot overcome the soldier of Christ by the weapons of the foe, he lays him low by his own spear.
Reproduced in full. Translation: Nicene and Post-Nicene Fathers, series 2, vol. 11 (Schaff and Wace, 1894), public domain (Public domain).