It is not always possible to fulfill the usual rules; one must take circumstances into account and try to fulfill what they make possible, as far as one can. The demons themselves are not unmindful of this law. So, being in constant enmity with us, they prevent us from doing what is possible and urge us to do what is impossible.
A greedy appetite for food is terminated by satiety and the pleasure of drinking ends when our thirst is quenched. And so it is with the other things... But the possession of virtue, once it is solidly achieved, cannot be measured by time nor limited by satiety. Rather, to those who are its disciples it always appears as something ever new and fresh.
Do not be deluded by thoughts that virtue exceeds your powers and is impossible for you; but, inspired by faith, boldly make a beginning, show before God your good will and diligence - and you will see the help He will send you to practice virtue.
Brothers, as long as you have breath in your bodies, strive for your salvation. Before the hour comes in which we shall weep for ourselves, let us practice virtue eagerly. For I tell you that if you knew what good things are in heaven, what promise is laid up for the saints and how those who have fallen away from God are punished and also what torments are laid up for those who have been negligent – especially those who have known the truth and have not led a way of life worthy of it so as to inherit that blessedness which is reserved for the saints and to flee the punishments of these torments – then you would endure every pain in order to be made perfect in the virtue which is according to Christ.
The blacksmith, who pounds a piece of iron, has previously thought about what he wants to make- a sickle, a knife, an axe - and works accordingly. And so let the man of God ponder in advance which virtue he wishes to acquire, in order not to toil aimlessly.
A mind from which the thought of God has been carried away and which has thus become far removed from remembering Him, is also indifferent to sin with the outer senses. For such a mind can guide neither the hearing nor the tongue, since zest to work on itself has gone out of it.
The virtues follow one from another in succession, so that the path of virtue does not become grievous and burdensome, and so that by being achieved in order progressively they may be made light; thus the hardships endured for virtue's sake should be cherished by a man as is the good itself.
The abstinent withdraws from gluttony, the uncovetous from covetousness, the silent from wordiness, the pure from attachment to sensory pleasures, the chaste from fornication, he who is content with what he has from love of money, the meek from agitation (anger), the humble from vanity, the obedient from objection, he who is honest with himself from hypocrisy; equally, he who prays withdraws from despair, the willing pauper from acquisitiveness, he who professes his faith from denying it, the martyr from idolatry – so you see that each virtue, performed even unto death, is nothing but withdrawal from sin; and withdrawal from sin is a natural action, not an action which could be rewarded by the kingdom.
Do not be surprised that when you draw near to virtue, grievous and intense tribulations come to you on all sides: for virtue is not considered virtue, if it does not involve hard work.