We have said that the passions are not in themselves evil; all can without exception be turned to good.
a. Love and joy can be directed towards pure and lawful family-affection, towards good and supernatural friendship, but chiefly towards good and supernatural friendship, but chiefly towards Our Lord, Who is the most tender, the most generous, the most devoted of friends. This, the, is what matters most, that we center our hearts in Him by reading, meditation, and by actually carrying out in our lives the teachings in the two chapters of the Following of Christ (Thomas a’ Kempis’ Imitation of Christ), “On the love of Jesus above all things,” and “On familiar friendship with Jesus”, two chapters which have proved a potent source of inspirations to many souls.
b. Hatred and aversion can be turned against sin, against vice, and against whatever leads to them, in order that we may loathe them and fly from them: “I have hated iniquity.”
c. Desire is transformed into lawful ambition; into the natural ambition of doing honor to one’s family, one’s country, and into the supernatural ambition of becoming a saint, an apostle.
d. Sadness, instead of degenerating into melancholy, becomes a sweet resignation under trials, which are for the Christian soul a seed of glory; or it is changed into tender compassion for the suffering Christ, loaded down with insults; or it is turned towards afflicted souls.
e. Hope becomes a Christian virtue of unfailing trust in God and multiplies our energies for good.
f. Despair takes the form of rightful mistrust of self, based upon our own insufficiency and our sins, but tempered by trust in God.
g. Fear is no longer that sense of depression which weakens the soul; but in the Christian it I a source of power. The Christian fears sin, he fears hell; but this righteous fear inspires him with courage in the struggle against evil. He fears God above all, he dreads to offend his Maker, and treads under foot human respect.
h. Anger instead of causing us to lose self-control, is but a just and holy indignation that strengthens us against evil.
i. Boldness becomes prowess in the faces of obstacles and dangers; the greater the difficulty we encounter, the more eager we are to make efforts to overcome it.
To attain these happy results, there is nothing like meditation, accompanied by devout affections and generous resolutions. Thereby, we conceive an ideal, and form deep-seated convictions that help us daily to approach that ideal. The purpose in view is to evoke and nurture in the soul such thoughts and feelings as are in harmony with the virtues we want to practice, and to remove images and impression allied to the vices we want to shun…
Source: The Spiritual Life: A Treatise on Ascetical and Mystical Theology, 802-803