60 This modesty is nourished by the fear of God, that filial fear which is founded on the virtue of profound Christian humility, and which creates in us utter abhorrence for the slightest sin, as Our predecessor, St. Clement I, stated in these words, "he who is chaste in flesh should not be proud, for he should know that he owes the gift of continence to another." How important Christian humility is for the protection of virginity, no one perhaps has taught more clearly than Augustine. "Because perpetual continence, and virginity above all, is a great good in the saints of God, extreme vigilance must be exercised lest it be corrupted by pride. . . The more clearly I see the greatness of this gift, the more truly do I fear lest it be plundered by thieving pride. No one therefore protects virginity, but God Himself Who bestowed it: and 'God is charity.' The guardian therefore of virginity is charity; the habitat of this guardian is humility."
Source: Sacra Virginitas (Vatican.va)