For Whom the Bell Tolls by John Donne

No man is an island, entire of itself; every man is a piece of the
continent, a part of the main. If a clod be washed away by the sea,
Europe is the less, as well as if a promontory were, as well as if a 
Manor of thy friend’s or of thine own were: any man’s death diminishes
me, because I am involved in mankind, and therefore never
send to know for whom the bell tolls; it tolls for thee.