52 Here are the helps, commended to us by our Divine Redeemer, by which we may efficaciously protect our virtue: constant vigilance, whereby we diligently do all that we can; moreover, constant prayer to God, asking for what we cannot attain by ourselves, because of our weakness. "Watch and pray, that you enter not into temptation. The spirit indeed is willing, but the flesh is weak." A vigilance which guards every moment of our lives and every type of circumstance is absolutely necessary for us: "For the flesh lusteth against the spirit: and the spirit against the flesh." But if anyone grants however little to the enticements of the flesh, he will see himself quickly pulled toward those "works of the flesh" which the Apostle lists, the basest and ugliest vices of man.
Source: Sacra Virginitas (Vatican.va)