Nabokov (Speak, Memory):
The cradle rocks above an abyss, and common sense tells us that our existence is but a brief crack of light between two eternities of darkness. Although the two are identical twins, man, as a rule, views the prenatal abyss with more calm than the one he is heading for.
William Hazlitt (On the Fear of Death):
Perhaps the best cure for the fear of death is to reflect that life has a beginning as well as an end. There was a time when we were not: this gives us no concern -- why, then, should it trouble us that a time will come when we shall cease to be?