The Talmud

Menachot 85a

Johana and Mamre [aka Jannes and Jambres] said to Moses, 'Wouldst thou carry straw to Hafaraim?' (Evidently, the town of Hafaraim must have had plenty of straw, so when describing a wasted effort, it was likened to carrying straw to Hafaraim. It therefore is similar to the more modern English expression "to carry coals to Newcastle.") He answered them, 'There is a common saying. "Bring herbs to Herbtown".' [footnote states, "For all merchants flock there and the demand for herbs is great."]