Sunan an-Nasa'i

It was narrated that Abu Hurairah said: "The Messenger of Allah forbade meeting (the traders on the way) a Muhajhir selling for a Bedouin, keeping the milk in the udder of an animal (so as to increase its price), artificially inflating prices, a man to urge the cancellation of sale already agreed upon and a woman to ask that her sister (in faith) be divorced"