E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Friday, an Unlucky Day.
Because it was the day of our Lords crucifixion; it is accordingly a fast-day in the Roman Catholic Church. Soames says, Adam and Eve ate the forbidden fruit on a Friday, and died on a Friday. (Anglo-Saxon Church, p. 255.)
But once on a Friday (tis ever they say),
A day when misfortune is aptest to fail.
Saxe: Good Dog of Bretté, stanza 3.
In Spain, Friday is held to be an unlucky day. So is it esteemed by Buddhists and Brahmins. The old Romans called it nefastus, from the utter overthrow of their army at Gallia Narbonensis. And in England the proverb is that a Friday moon brings foul weather.