“If there were no such creatures as minstrel-maidens, it would be necessary to invent them.”

Si Dieu n'existait pas, il faudrait l'inventer.
Variant translation: If there was no God, It would be necessary to invent him.
Épître à l'Auteur du Livre des Trois Imposteurs (10 November 1770)
For the background of the quote see this source: Yeh, Anthony (July 3, 2011). "What did Voltaire mean when he said that "if God did not exist, it would be necessary to invent him"?" http://archive.is/Rt53S. Quora. Archived from the original https://www.quora.com/What-did-Voltaire-mean-when-he-said-that-if-God-did-not-exist-it-would-be-necessary-to-invent-him on October 27, 2017. Retrieved October 27, 2017.
Citas

The Monthly Magazine

Source: god is Not Great: How Religion Poisons Everything

Source: Shadow & Claw

Chpt.3, p. 34
Principles of Geology (1832), Vol. 1
Context: It may be well to forewarn our readers that in tracing the history of geology from the close of the seventeenth to the end of the eighteenth century they must expect to be occupied with accounts of the retardation as well as of the advance of the science.... It will be necessary to dwell on futile reasoning and visionary hypothesis because the most extravagant systems were often invented or controverted by men of acknowledged talent.

Reportedly to Alexander Graham Bell after a demonstration of the telephone, as quoted in Future Mind : The Microcomputer-New Medium, New Mental Environment (1982) by Edward J. Lias, p. 2 but author did not footnote or in any other way cite a source for the quotation, and the Rutherford B. Hayes Presidential Center has found no primary-source evidence that Rutherford B. Hayes made the comment. The same article erroneously states that President Hayes had his first experience with the telephone in 1876 in a "trial conversation between Washington and Philadephia." Rutherford B. Hayes was president of the United States in the years 1877-1881. His well documented experience with the telephone occurred in 1877 while Hayes was in Rhode Island. Prior to becomng disputed here, this statement was treated as probably spurious in "Obama’s whopper about Rutherford B. Hayes and the telephone" in the Washington Post (16 March 2012) http://www.washingtonpost.com/blogs/fact-checker/post/obamas-whopper-about-rutherford-b-hayes-and-the-telephone/2012/03/15/gIQAel6SFS_blog.html?wprss=fact-checker, which asserts Hayes installed a phone only months later, and that the Providence Journal (29 June 1877) reported his words during the demonstration as "That is wonderful!"
Disputed

Source: No Enemy But Time (1982), Chapter 10 “Fruit of the Looms” (p. 76)

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 156.