DESTINY, n. A tyrant’s authority for crime, and a fool’s excuse for failure.

Ambrose Bierce (1842-1914?) American writer and journalist

“Destiny,” The Cynic’s Word Book (1906)
    (Source)

Included in The Devil's Dictionary (1911).

In the original entry, published in the "Devil's Dictionary" column in the San Francisco Wasp (1882-03-03), the definition was given as:

A force alleged to control affairs, principally quoted by erring human beings to excuse their failures.