He informed him that the Messenger of Allah ﷺ said, "Beware of Qassama."We asked, "What is Qassama?"He replied, "It is something shared among people, and one comes and takes a portion from it for himself."
أخبره، أن رسول الله ﷺ قال: إياكم والقسامة. قال: فقلنا: وما القسامة؟ قال: الشيء يكون بين الناس فيجيء فينتقص منه.
Abu Dawud (2783) narrated it, and from his route Bayhaqi (6/356), from Jafar bin Musafir Tinnisi, who said, Ibn Abu Fudayk told us, Zumai told us, from Zubayr bin Uthman bin Abdullah bin Suraqa, that Muhammad bin Abdul-Rahman bin Thawban informed him, that Abu Saeed Khudri informed him, and he related it. Zubayr bin Uthman bin Abdullah bin Suraqa had no one narrate from him except Zumai, who is Musa bin Yaqub, and no one deemed him reliable except that Ibn Hibban mentioned him among his trustworthy narrators. This is why Hafiz said, "Acceptable," meaning when corroborated, but I did not find any corroboration for him.However, I found a mursal hadith with a sahih chain from Ata bin Yasar that the Messenger of Allah ﷺ said, "Beware of qasama." He said, so we asked, "What is qasama?" He said, "It is when a man is in charge of a large group of people and takes from the share of this one and the share of that one."Abu Dawud (2784) and Bayhaqi (6/356) both narrated it through the route of Sharik bin Abu Nimr, from Ata bin Yasar, and he related it. This mursal narration strengthens the marfu one, and through it the hadith rises to the level of hasan, Allah willing.Khattabi said, "Qasama, with the qaf vocalized with damma, is a name for what the one dividing shares takes for himself during the division, like nushara for what is left over from sawing, fisala for what is set aside from a weaned animal, and ujala for what is hastily prepared as food for a guest. He said, this does not constitute a prohibition of the wage of the divider if he takes it with the permission of those for whom the division is made. Rather, this came regarding one who was placed in charge of a people's affairs, serving as their overseer or representative, and when he divided their shares among them, he withheld something for himself, taking it for his own benefit at their expense. An explanation of this has come in another hadith." End of quote.