In about 300 B.C., Epicurus eloquently summed up the problem of the existence of evil. It has come to be known as the Riddle of Epicurus or the Epicurean paradox. It was translated by David Hume in the Dialogues concerning Natural Religion:
If God is willing to prevent evil, but is not able to
Then He is not omnipotent.
If He is able, but not willing
Then He is malevolent.
If He is both able and willing
Then whence cometh evil?
If He is neither able nor willing
Then why call Him God?