“Let your desires be governed by reason.”

Source: The Guardian

Twelve Virtues Of Rationality http://yudkowsky.net/rational/virtues
Context: Do not flinch from experiences that might destroy your beliefs. The thought you cannot think controls you more than thoughts you speak aloud. Submit yourself to ordeals and test yourself in fire. Relinquish the emotion which rests upon a mistaken belief, and seek to feel fully that emotion which fits the facts. If the iron approaches your face, and you believe it is hot, and it is cool, the Way opposes your fear. If the iron approaches your face, and you believe it is cool, and it is hot, the Way opposes your calm. Evaluate your beliefs first and then arrive at your emotions. Let yourself say: “If the iron is hot, I desire to believe it is hot, and if it is cool, I desire to believe it is cool.”

Source: Macbeth

The Voice of the Devil
Source: 1790s, The Marriage of Heaven and Hell (1790–1793)

Source: Macbeth

Book III, 1287a.32
Politics
Variant: The Law is reason free from passion.

Source: https://guardian.ng/features/how-to-have-more-female-vice-chancellors-in-nigerian-varsities/Prof Grace Alele on allowing qualified people in position regardless of the gender.

X. Concerning Virtue and Vice.
On the Gods and the Cosmos
Context: The doctrine of virtue and vice depends on that of the soul. When the irrational soul enters into the body and immediately produces fight and desire, the rational soul, put in authority over all these, makes the soul tripartite, composed of reason, fight, and desire. Virtue in the region of reason is wisdom, in the region of fight is courage, in the region of desire is temperance; the virtue of the whole soul is righteousness. It is for reason to judge what is right, for fight in obedience to reason to despise things that appear terrible, for desire to pursue not the apparently desirable, but, that which is with reason desirable. When these things are so, we have a righteous life; for righteousness in matters of property is but a small part of virtue. And thus we shall find all four virtues in properly trained men, but among the untrained one may be brave and unjust, another temperate and stupid, another prudent and unprincipled. Indeed, these qualities should not be called virtues when they are devoid of reason and imperfect and found in irrational beings. Vice should be regarded as consisting of the opposite elements. In reason it is folly, in fight, cowardice, in desire, intemperance, in the whole soul, unrighteousness.
The virtues are produced by the right social organization and by good rearing and education, the vices by the opposite.