Al-Harith said: "He who possesses a trait that is more complete than his reason, that trait is most likely to be the cause of his death."
The Arabs used to say: "He whose reason is not the dominant trait among his virtues, his destruction shall lie within the dominant trait among his vices," and this refers to practice and habit.
By the chain of transmission from Yazid ibn Habib, who said: "The scholars find enjoyment through their intellects." He also said: "He who does not contemplate a matter with the eye of his reason, the sword of his ingenuity will only strike his own vital spots."
(35) Aristotle, may his might be glorified, said: "Reason, when it is corrupted, is like a gemstone when it is shattered."
(36) He also said: "The rational person is he who restrains his tongue, and the ignorant person is he who is ignorant of his own worth."
A sage said: "Reason and deliberation are twins (as are forbearance and etiquette); they are produced by high ambition."
He also said: "Patience is a strength derived from reason; so, in proportion to the substance of reason, patience grows strong."
Gregory said: "Reason is innate in the natures of animals because it is the completion of creation and the seal of movement. Its power resides in its dwelling place, which is the moisture of the brain that strengthens the nerves. Its movement originates from the right side of the heart, because the whim (al-hawa) that opposes reason originates from the left side of the heart. Goodness, knowledge, forbearance, deliberation, and safety come from reason; while evil, ignorance, corruption, and recklessness come from the whim generated from the left side of the heart."
Pythagoras said: "Reason is a simple radiance within a simple, subtle moisture in the animal, which is polished by the 'hands' of the acquired intellect through the five senses. When these acquired descriptions through the five senses grow strong, the veils are removed, its brilliance increases, and its light becomes great—just as a gemstone is polished and thus shines."