A man remains wise as long as he seeks wisdom. The minute he thinks he has found it, he becomes a fool. (Traditional Proverb)
A king learns by his ears a saint by his intellect a beast by his nose and a fool by his experience. (Traditional Proverb)
A fool may be known by six things anger, without cause speech, without profit change, without progress inquiry, without object putting trust in a stranger, and mistaking foes for friends (Traditional Proverb)