On the prohibition against cheating and deceit

Riyad as-Salihin by Imam Nawawi 276. Chapter: On the prohibition against cheating and deceit Allah Almighty says, "And those who abuse believing men and woman, when they have not merited it, bear the weight of slander and clear wrongdoing." (33:58) 1579. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Anyone who carries arms against us is not one of us. Anyone who cheats us is not one of us." [Muslim] In one variant of his is that the Messenger of Allah, may Allah bless him and grant him peace, passed by a heap of grain and put his hand into it and his fingers came upon some dampness. He said, "Owner of this grain, what is this?" He said, "The rain caught it, Messenger of Allah." He said, "Why did you not put it on top of the heap so that the people could see it! Anyone who cheats us is not one of us." 1580. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Do not bid against each other in order to raise the price." [Agreed upon] 1581. Ibn 'Umar reported that the Prophet, may Allah bless him and grant him peace, forbade outbidding others merely in order to raise the price." [Agreed upon] 1582. Ibn 'Umar said that a man mentioned to the Prophet, may Allah bless him and grant him peace, that he was frequently deceived in business. He said, "When you buy, say, 'No cheating.'" [Agreed upon] 1583. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Anyone who corrupts a man's wife or slave is not one of us." [Abu Dawud]