Do not neglect the practice of the virtues; if you do, your spiritual knowledge will decrease, and when famine occurs you will go down into Egypt (Genesis 41:57, 46:6).
No Christian believing rightly in God should ever be off his guard. He should always be on the look-out for temptation, so that when it comes he will not be surprised or disturbed, but will gladly endure the toil and affliction it causes, and so will understand what he is saying when he chants with the prophet: 'Prove me, O Lord, and try me' (Ps. 26:2 LXX). For the prophet did not say, 'Thy correction has destroyed me,' but, 'it has upheld me to the end' (Ps. 18:35 LXX).
I wonder at our free will: it is strong, and yet it has been overthrown. It is a master, yet it has become a slave. It has the opportunity to conquer, yet it would rather yield and be conquered itself. Although it is free, it gives itself to slavery, like a bondswoman who signs with her own hand the agreement that binds her.
In this order, and by this succession, the ecclesiastical tradition from the apostles, and the preaching of the truth, have come down to us. And this is most abundant proof that there is one and the same vivifying faith, which has been preserved in the Church from the apostles until now, and handed down in truth.
Just as one cannot buy education or artistic skills for any price without working at it, so one cannot attain the habit of exercising the virtues without zeal and diligence.
Woe is he who knowingly chooses to sin with the intention to repent when morning comes, for he knows not what the coming day or the night that precedes it will bring.
A haughty person is not aware of his faults, or a humble person of his good qualities. An evil ignorance blinds the first, an ignorance pleasing to God blinds the second.