In all his dealings, a Muslim is supposed to be transparent and Allah-fearing. He is not allowed to deceive others or to cheat them. He must point out any defects in his wares to a potential buyer. There are many Qur’anic verses and Prophetic Hadiths that are clear warnings for those who cheat and deceive. There are so many special references in the Qur’an and the Sunnah to the prohibition of cheating in buying and selling that the Prophet (peace and blessings be upon him) said, “He who deceives us is not one of us.”
The Prophet (peace and blessings be upon him) warned people against reducing the value of people’s property and cheating in weights and measures.
In the Qur’an, Allah has condemned cheating and the people who do it and has warned them of bad consequences. This may be understood from the following verses. “Woe unto the defrauders — Those who when they take the measure from mankind demand it full. But if they measure unto them or weigh for them, they cause them loss. Do such (men) not consider that they will be again unto an awful Day, the day when (all) mankind stand before the Lord of the Worlds?” (Al-Mutaffifeen: 1-6)
The above verses constitute a severe warning to those who cheat in weights and measures, and the warning is all the more so to who steal, embezzle and withhold from the people the things that are their due. These are more deserving of the warning than those who cheat in weights and measures.
Similarly, the Prophet (peace and blessings be upon him) cautioned us against cheating and warned the one who does this. The Prophet (peace and blessings be upon him) passed by a pile of food and put his hand into it, and his fingers touched something wet. He said, “What is this, O seller of the food?” The man said, “It got rained on, O Messenger of Allah.” He said, “Why did you not put it (the wet part) on top of the pile so that the people could see it? He who deceives does not belong to me.”
According to other reports, “He who deceives us is not one of us.” (Reported by Muslim).
The above warning “He is not one of us” is a sufficient warning against cheating and sufficient deterrent against cheating in buying and selling.
Nowadays, we desperately need to instill this message in our hearts so that we might stir the conscience and be aware that Allah is watching all that we do, without the need for any human supervisor.