Gregory of Nyssa

Thus our love of pleasure took its beginning from our being made like to the irrational creation, and was increased by the transgressions of men, becoming the parent of so many varieties of sins arising from pleasure as we cannot find among the irrational animals. Thus the rising of anger in us is indeed akin to the impulse of the brutes; but it grows by the alliance of thought: for thence come malignity, envy, deceit, conspiracy, hypocrisy; all these are the result of the evil husbandry of the mind; for if the passion were divested of the aid it receives from thought, the anger that is left behind is short-lived and not sustained, like a bubble, perishing straightway as soon as it comes into being. Thus the greediness of swine introduces covetousness, and the high spirit of the horse becomes the origin of pride; and all the particular forms that proceed from the want of reason in brute nature become vice by the evil use of the mind.

So, likewise, on the contrary, if reason instead assumes sway over such emotions, each of them is transmuted to a form of virtue; for anger produces courage, terror caution, fear obedience, hatred aversion from vice, the power of love the desire for what is truly beautiful; high spirit in our character raises our thought above the passions, and keeps it from bondage to what is base; yea, the great Apostle, even, praises such a form of mental elevation when he bids us constantly to "think those things that are above;" and so we find that every such motion, when elevated by loftiness of mind, is conformed to the beauty of the Divine image.