“a friend is a second self”

“To study philosophy is nothing but to prepare one’s self to die.”

“Never injure a friend, even in jest.”

“The shifts of fortune test the reliability of friends.”

“Your enemies can kill you, but only your friends can hurt you.”

“Every man can tell how many goats or sheep he possesses, but not how many friends.”

“Everyone has the obligation to ponder well his own specific traits of character. He must also regulate them adequately and not wonder whether someone else's traits might suit him better. The more definitely his own a man's character is, the better it fits him.”