I am very grateful to you for rejecting atheism and for liking this line: “If God did not exist, it would be necessary to invent Him.” I am rarely satisfied with my verses, but I own I have a father’s tenderness for that one.

[Je vous sais bien bon gré de réprouver l’athéisme, et d’aimer ce vers: “Si Dieu n’existait pas, il faudrait l’inventer.” Je suis rarement content de mes vers, mais j’avoue que j’ai une tendresse de père pour celui-là.]

Voltaire (1694–1778) French writer [pseud. of Francois-Marie Arouet]

Letter (1770-11-10) to Bernard-Joseph Saurin

(Source (French)). Found in Œuvres complètes de Voltaire, tome 47 (1882), as letter 8080.

See more about that line here.