Known sourcecanonical
"When I see a merchant over-polite to his customers, begging them to taste a little brandy and throwing half his goods on the counter,--thinks I, that man has an axe to grind."
Charles Miner / Who 'll turn Grindstones.
Who 'll turn Grindstones.
Bartlett's Familiar Quotations, 9th ed. (Little, Brown, 1905), public domain