E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
I shant buy my Attic figs in future, but grow them. Dont count your chickens before they are hatched. It was Xerxes who boasted that he did not intend any longer to buy his figs, because he meant to conquer Attica and add it to his own empire; but Xerxes met a signal defeat at Salamis, and never loosed his sandal till he reached Abdera.
In the name of the Prophet, Figs! A burlesque of the solemn language employed in eastern countries in the common business of life. The line occurs in the imitation of Dr. Johnsons pompous style, in Rejected Addresses, by James and Horace Smith.