“I think that if there were a God, there would be less evil on this earth. I believe that if evil exists here below, then either it was willed by God or it was beyond His powers to prevent it. Now I cannot bring myself to fear a God who is either spiteful or weak. I defy Him without fear and care not a fig for his thunderbolts.”

29a–b
Alternate translation: "To fear death, is nothing else but to believe ourselves to be wise, when we are not; and to fancy that we know what we do not know. In effect, no body knows death; no body can tell, but it may be the greatest benefit of mankind; and yet men are afraid of it, as if they knew certainly that it were the greatest of evils."
Plato, Apology

Source: Attributed in posthumous publications, Einstein and the Poet (1983), p. 132
Variant transcription from "Death of a Genius" in Life Magazine: "I cannot accept any concept of God based on the fear of life or the fear of death, or blind faith. I cannot prove to you that there is no personal God, but if I were to speak of him I would be a liar."
Context: About God, I cannot accept any concept based on the authority of the Church. As long as I can remember, I have resented mass indoctrination. I do not believe in the fear of life, in the fear of death, in blind faith. I cannot prove to you that there is no personal God, but if I were to speak of him, I would be a liar. I do not believe in the God of theology who rewards good and punishes evil. My God created laws that take care of that. His universe is not ruled by wishful thinking, but by immutable laws.

Source: 2000s, Letter to a Christian Nation (2006), p. 55

Variant: I knew then that I hadn't stopped believing in God. I'd just stopped believing God cared. There might be a God, Clary, and there might not, but I don't think it matters. Either way we're on our own.
Source: City of Bones

XII. The origin of evil things; and that there is no positive evil.
On the Gods and the Cosmos
Context: If evil exists it must exist either in Gods or minds or souls or bodies. It does not exist in any God, for all god is good. If anyone speaks of a "bad mind" he means a mind without mind. If of a bad soul, he will make the soul inferior to body, for no body in itself is evil. If he says that evil is made up of soul and body together, it is absurd that separately they should not be evil, but joined should create evil.

[2005, Stations of Wisdom, World Wisdom, 102, 978-0-94153218-1]
God, Reverential fear and love

Canto III, lines 61–63 (tr. Mark Musa).
The Divine Comedy (c. 1308–1321), Inferno

This attribution occurs in chapter 13 (Ioan. Graphei, 1532, p. 494) http://books.google.com/books?id=rs47AAAAcAAJ&pg=PA494 of the Christian church father's Lactantius's De Ira Dei (c. 318):
"God," he [Epicurus] says, "either wants to eliminate bad things and cannot,
or can but does not want to,
or neither wishes to nor can,
or both wants to and can.
If he wants to and cannot, then he is weak and this does not apply to god.
If he can but does not want to, then he is spiteful which is equally foreign to god’'s nature.
If he neither wants to nor can, he is both weak and spiteful, and so not a god.
If he wants to and can, which is the only thing fitting for a god, where then do bad things come from? Or why does he not eliminate them?"
Lactantius, On the Anger of God, 13.19
Charles Bray, in his 1863 The Philosophy of Necessity: Or, Natural Law as Applicable to Moral, Mental, and Social Science quotes Epicurus without citation as saying a variant of the above statement (p. 41) http://books.google.com/books?id=BebVAAAAMAAJ&pg=PA41 (with "is not omnipotent" for "is impotent"). This quote appeared in "On the proofs of the existence of God: a lecture and answer questions" http://www.atheism.ru/old/KryAth2.html (1960) by professor Kryvelev I.A. (Крывелёв И.А. О доказательствах бытия божия: лекция и ответы на вопросы. М., 1960). And N. A. Nicholson, in his 1864 Philosophical Papers (p. 40), attributes "the famous questions" to Epicurus, using the wording used earlier by Hume (with "is he" for "he is") http://books.google.com/books?id=ZMsGAAAAcAAJ&pg=PA40. Hume's statement occurs in Book X (p. 186) http://books.google.com/books?id=E7dbAAAAQAAJ&pg=PA186 of his renowned Dialogues Concerning Natural Religion, published posthumously in 1779. The character Philo precedes the statement with "Epicurus's old questions are yet unanswered.…". Hume is following the enormously influential Dictionnaire Historique et Critique (1697–1702) of Pierre Bayle, which quotes Lactantius attributing the questions to Epicurus (Desoer, 1820, p. 479) http://books.google.com/books?id=QwwZAAAAYAAJ&pg=PA479.
There has also arisen a further disputed extension, for which there has been found no published source prior to The Heretic's Handbook of Quotations: Cutting Comments on Burning Issues (1992) by Charles Bufe, p. 186: "Is he neither able nor willing? Then why call him God?"
Disputed

Quoted in " Goodbye Margherita Hack, “The Lady of the Stars.”", iitaly.org (1 July 2013) http://www.iitaly.org/magazine/focus/facts-stories/article/goodbye-margherita-hack-lady-stars?mode=colorbox.