A Christian has great difficulty in attaining three things: grief (over sins), tears, and the continual memory of death. Yet these contain all of the other virtues.
We ought to learn the virtues through practicing them, not merely through talking about them, so that by acquiring the habit of them we do not forget what is of benefit to us. 'The kingdom of God,' St. Paul says, 'resides not in words but in power' (I Cor. 4:20). For he who tries to discover things through actual practice will come to understand what gain or loss lies in any activity that he pursues.
The principle and source of the virtues is a good disposition of the will, that is to say, an aspiration for goodness and beauty. God is the source and ground of all supernal goodness. Thus the principle of goodness and beauty is faith or, rather, it is Christ, the rock of faith, Who is the principle and foundation of all the virtues. On this rock we stand and on this foundation we build every good thing.
If you believe in a Divine Providence which determines the earthly fate of everyone and the way by which he is to be saved, you must also believe that the disposition of your life is the most suitable for you in working out your salvation.
We must with unflagging zeal and care give ourselves to the pursuit of virtue, and constantly occupy ourselves in its practice, lest at any time progress may cease, and regress immediately take its place.... To cease to acquire means to lose, for the will which goes no longer forward will not be far from peril of falling back.
Nothing that happens to us is contrary to the will of Providence, and everything that is sent us by God is for our good and the salvation of our soul. Even if it does not seem helpful at the moment, we shall understand later on that it was willed so by God, and that it is not what we ourselves wish that is always useful to us. God sends trials out of his Mercy, so that after we have suffered, we may be crowned by Him. Without temptation it is impossible to receive a crown. This is why we should thank God for these sufferings, as out Benefactor and Savior.
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 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.
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.
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.