To die, to sleep— No more, and by a sleep to say we end The heartache and the thousand natural shocks That flesh is heir to—'tis a consummation Devoutly to be wished. To die, to sleep. To sleep, perchance to dream. Ay, there's the rub, For in that sleep of death what dreams may come When we have shuffled off this mortal coil Must give us pause.
William Shakespeare (1564–1616), British dramatist, poet. Hamlet, in Hamlet, act 3, sc. 1, l. 62-70 (1604).
Part of Hamlet's meditative soliloquy on the question of "To be, or not to be." Sleep was proverbially the image of death; "rub" means snag (a term from the game of bowls); "coil" means turmoil.