Sahih Bukhari, Chapter: Conditions

Allah's Apostle (SAW) forbade: (1) the meeting of the caravan (of goods) on the way, (2) that a residing person sells goods of a bedouin, (3) that a woman stipulates the divorce of the wife of the would-be husband, (4) that a man tries to cause the cancellation of a bargain concluded by another. He also forbade An-Najsh (see Hadith 837) and that one withholds the milk in the udder of the animal so that he may deceive people on selling it.