It is of great advantage that man should know his station, and not imagine that the whole universe exists only for him.

The people who are abroad are all those that have no religion, neither one based on speculation nor one received by tradition. Such are the extreme Turks that wander about in the north, the Kushites who live in the south, and those in our country who are like these. I consider these as irrational beings, and not as human beings; they are below mankind, but above monkeys, since they have the form and shape of man, and a mental faculty above that of the monkey.

Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime.

Do not imagine that these most difficult problems can be thoroughly understood by any one of us.

If a person studies too much and exhausts his reflective powers, he will be confused, and will not be able to apprehend even that which had been within the power of his apprehension. For the powers of the body are all alike in this respect.

He who immerses himself in sexual intercourse will be assailed by premature aging, his strength will wane, his eyes will weaken, and a bad odour will emit from his mouth and his armpits, his teeth will fall out and many other maladies will afflict him.

The goal of good health is to enable a person to acquire wisdom.