Sweetness and light is an English idiom that can be used in common speech, either as statement of personal happy consciousness, (though this may be viewed by natives as being a trifle in earnest) or as literal report on another person. Depending upon sense-of-humour, some may use the phrase with mild irony. For example: The two had been fighting for a month, but around others it was all sweetness and light.[1] Esteemed humorous writer P. G. Wodehouse employed the phrase often, sometimes with a slight nod to the phrase's dual-edge. Originally, however, "sweetness and light" had a special use in literary and cultural criticism meaning "pleasing and instructive", which in classical theory was considered to be the aim and justification of poetry.[2]
Jonathan Swift first used the phrase in his mock-heroic prose satire, "The Battle of the Books" (1704), a defense of Classical learning, which he published as a prolegomenon to his A Tale of a Tub. It gained widespread currency in the Victorian era, when English poet and essayist Matthew Arnold picked it up as the title of the first section of his 1869 book Culture and Anarchy: An Essay in Political and Social Criticism, where "sweetness and light" stands for beauty and intelligence, the two key components of an excellent culture.