Thine own friend, and thy father’s friend, forsake not.
—The Book of Proverbs
The only good friends are old friends.
—Voltaire
Whosoever formeth an intimacy with the enemies of his friends, does so to injure the latter. O wise man! wash your hands of that friend who associates with your enemies.
—Saadi
To thrust aside a virtuous friend, I consider as bad as to thrust away one’s own life, which one loves best.
—Sophocles
Friendship is one soul in two bodies.
—Pythagoras