In Jewish Bankers and the Holy See (2012), León Poliakov cites a joke current in 12th-century ghettos to justify usury between Jews.

“It consisted, it is said, of reciting Deuteronomy 23:20 in interrogative tones to make it mean the opposite of its obvious sense:

“‘Unto a foreigner thou mayest lend upon usury; but unto thy brother thou shalt not lend upon usury?'”