ALL VICES, once cast down, fade in their strength and are more readily blocked and slipped in subsequent entanglements. But vainglory, when thrown, surges back with fiercer vigor to the grapple; thought vanquished, from its feint it rallies alive, redoubling might. Such is the subtle guile of the enemy who turns the soldier of Christ’s own prowess against him, felling by the soldier’s own valor when direct assault may not prevail.
St. John Cassian, The Institutes, XI, 7.