Examine from time to time what are the dominant passions of your soul, and having ascertained this, mould your life, so that in thought, word and deed you may as far as possible counteract them.
For instance, if you know that you are disposed to be vain, reflect often upon the emptiness of this earthly life, call to mind how burdensome all mere earthly vanities will be to the conscience at the hour of death, how unworthy of a generous heart, how puerile and childish, and the like. See that your words have no tendency to foster your vanity, and even though you may seem to be doing so but reluctantly, strive to despise it heartily, and to rank yourself in every way among its enemies. Indeed, by dint of steady opposition to anything, we teach ourselves to hate even that which we began by liking.
Do as many lowly, humble deeds as lie in your power, even if you perform them unwillingly at first; for by this means you will form a habit of humility, and you will weaken your vanity, so that when temptation arises, you will be less predisposed to yield, and stronger to resist. Or if you are given to avarice, think often of the folly of this sin, which makes us the slave of what was made only to serve us; remember how when we die we must leave all we possess to those who come after us, who may squander it, ruin their own souls by misusing it, and so forth. Speak against covetousness, commend the abhorrence in which it is held by the world; and constrain yourself to abundant almsgiving, as also to not always using opportunities of accumulation.
If you have a tendency to trifle with the affections, often call to mind what a dangerous amusement it is for yourself and others; how unworthy a thing it is to use the noblest feelings of the heart as a mere pastime; and how readily such trifling becomes mere levity. Let your conversation turn on purity and simplicity of heart, and strive to frame your actions accordingly, avoiding all that savours of affectation or flirting.
In a word, let your time of peace,–that is to say, the time when you are not beset by temptations to sin,–be used in cultivating the graces most opposed to your natural difficulties, and if opportunities for their exercise do not arise, go out of your way to seek them, and by so doing you will strengthen your heart against future temptations