Last in the Battle, First in Origin

So it is most clearly established by examples and testimonies from Scripture that the mischief of pride, although it comes later in the order of the battle, is earlier in origin, and is the beginning of all sins and faults. Unlike the other vices, it is not simply fatal to the virtue opposed to it, which in this case is humility; it destroys all the virtues at once. Nor does it tempt only ordinary and small people, but chiefly those who already stand on the heights of valor. For this is how the prophet speaks of this spirit: “His food is choice.” [a]

So the blessed David guarded the recesses of his heart with the greatest care, so that he dared to say to him from whom the secrets of his conscience were not hidden, “Lord, my heart is not exalted, nor are my eyes lofty; nor have I walked in great matters, nor in wonderful things above me. If I was not humble in mind—”; and again, “He who works pride will not live in the midst of my house.” Yet he knew how hard that watchfulness is even for those who are perfect. So he did not presume on his own efforts, but prayed to God and begged his help, that he might escape unwounded by the arrows of this enemy, saying, “Let not the foot of pride come to me.” For he feared and dreaded falling under what is said of the proud: “God opposes the proud”; and again, “Everyone who exalts his heart is unclean before the Lord.”