If in this warfare we are provided with no weapons except self-distrust and trust in God, needful as both these are, we shall not only fail to gain the victory over ourselves, but shall fall into many evils. To these, therefore, we must add the use of Spiritual Exercises, the third weapon named above.
And these relate chiefly to the Understanding and the Will.
As regards the Understanding, we must guard against two things which are apt to obscure it.
One is ignorance, which darkens it and impedes it in acquiring the knowledge of truth, the proper object of the understanding. Therefore it must be made clear and bright by exercise, that so it may be able to see and discern plainly all that is needful to purify the soul from disorderly passions, and to adorn it with saintly virtues.
This light may be obtained in two ways. The first and most important is prayer, imploring the Holy Ghost to pour it into our hearts. This He will not fail to do, if we in truth seek God alone and the fulfillment of His holy will, and if in all things we submit our Judgment to that of our spiritual father.
The other is, to exercise ourselves continually in a true and deep consideration of all things, to discover whether they be good or evil, according to the teaching of the Holy Ghost, and not according to their outward appearance, as they impress the senses or are judged of by the world.
This consideration, if rightly exercised will teach us to regard as falsehood and vanity all which the blind and corrupt world in so many various ways loves, desires, and seeks after. It will show us plainly that the honors and pleasures of earth are but vanity and vexation of spirit; that injury and infamy inflicted on us by the world bring true glory, and tribulations contentment; that to pardon our enemies and to do them good is true magnanimity, and an act which likens us most nearly to God; that to despise the world is better than to rule it; that voluntary obedience for the love of God to the meanest of His creatures is greater and nobler than to command mighty princes; and that the mortification and subjugation of our most trifling appetite is more glorious than the reduction of strong cities, the defeat of mighty armies, the working of miracles, or the raising of the dead.
- taken from The Spiritual Combat, by Father Lorenzo Scupoli