Bukhari

Narrated Ibn `Umar: A man came to the Prophet and said, "I am often betrayed in bargaining." The Prophet advised him, "When you buy something, say (to the seller), 'No deception." The man used to say so afterwards.

And Allah the Exalted has said in Surah Al-Baqarah: «والله لا يحب الفساد‏» "Allah does not like corruption." And (the statement of Allah the Exalted in Surah Yunus:) «لا يصلح عمل المفسدين‏» "And Allah does not let the plan of the corrupters succeed." And Allah the Exalted has said (in Surah Hud): «أصلواتك تأمرك أن نترك ما يعبد آباؤنا أو أن نفعل في أموالنا ما نشاء » "Does your prayer command you that we should abandon what our forefathers used to worship, or that we should stop disposing of our wealth as we please?" And Allah the Exalted has said (in Surah An-Nisa): «ولا تؤتوا السفهاء أموالكم‏» "Do not give your wealth to the foolish, and do not act foolishly or deceitfully in a state of ignorance."

And Allah the Exalted has said in Surah Al-Baqarah: «والله لا يحب الفساد‏» "Allah does not like corruption." And (the statement of Allah the Exalted in Surah Yunus:) «لا يصلح عمل المفسدين‏» "And Allah does not let the plan of the corrupters succeed." And Allah the Exalted has said (in Surah Hud): «أصلواتك تأمرك أن نترك ما يعبد آباؤنا أو أن نفعل في أموالنا ما نشاء » "Does your prayer command you that we should abandon what our forefathers used to worship, or that we should stop disposing of our wealth as we please?" And Allah the Exalted has said (in Surah An-Nisa): «ولا تؤتوا السفهاء أموالكم‏» "Do not give your wealth to the foolish, and do not act foolishly or deceitfully in a state of ignorance."

Narrated Ibn `Umar: A man came to the Prophet and said, "I am often betrayed in bargaining." The Prophet advised him, "When you buy something, say (to the seller), 'No deception." The man used to say so afterwards.

Narrated Al-Mughira bin Shu`ba: The Prophet said, "Allah has forbidden for you, (1) to be undutiful to your mothers, (2) to bury your daughters alive, (3) to not to pay the rights of the others (e.g. charity, etc.) and (4) to beg of men (begging). And Allah has hated for you (1) vain, useless talk, or that you talk too much about others, (2) to ask too many questions, (in disputed religious matters) and (3) to waste the wealth (by extravagance).