friendship

Misfortune shows those who are not really friends.
Aristotle (384 BC - 322 BC), Eudemian Ethics

Do not protect yourself by a fence, but rather by your friends.
Czech Proverb

Be courteous to all, but intimate with few, and let those few be well tried before you give them your confidence. True friendship is a plant of slow growth, and must undergo and withstand the shocks of adversity before it is entitled to the appellation.
George Washington (1732 - 1799)

I've learned that all a person has in life is family and friends. If you lose those, you have nothing, so friends are to be treasured more than anything else in the world.
Trey Parker and Matt Stone, South Park, Prehistoric Ice Man, 1999