The Messenger of Allah (s) says:
“Whoever deceives another Muslim or harms him or even dislikes him is not one of us.”1
Like other acts it harms others as well as the deceiver.
How cheated you feel and how you complain if you buy food and then discover that it is bad and the seller has deceived you and has benefited himself at your expense!
How cheated you feel and how you complain if your watch is broken and you take it to a watch-maker to repair, but he deceives you about fixing it and after a few days it breaks down again with the same fault!
Indeed, you feel that these people are mischievous and troublesome and have misled you by taking your money in an unlawful (haram) way and by deceiving you and causing annoyance to you. You have the right to return the bad food to the one who cheated you and get your money back; and you have the right to return the watch to the watch-maker to repair it again because both tried to deceive you.
Surely, deceiving is unlawful and an immoral deed, so believers never do it.
Among our Islamic morals is to advise others both in speech and action on what is correct. Thus if one of us does something or carries out a task, it is obligatory for him to do it with sincerity and without deceiving people. If someone asks for advice, a believer should advise him truly without deceiving him.
Surely, the Holy Messenger (s) says: He who deceives Muslims is incomplete in belief and is not one of us!
As the Messenger of Allah (s) warned us against deceiving people through this hadith, he also warned us against any deed which causes harm and hurts others. Whoever causes harm to others intentionally is not a believer, so it is obligatory for a believer to indemnify people for any harm caused by him to them.
For example, the farmer who prevents water from reaching other farmers in order to destroy their crops is surely a destructive man who deliberately wants to cause harm. Whoever deliberately damages a footpath indeed causes harm to other people. These acts and others like them are intentionally damaging and cause destruction to society. A faithful should avoid doing anything which harms others. A Muslim is a useful man, who does good actions, tries to benefit others and never thinks of just himself.
Indeed, the Islamic religion wants a Muslim to deal with people in a straight manner - not to deceive or cheat them. Indeed, neither the cheater nor the deceiver are believers.
Among the examples of deceiving is the way some traders behave in order to cheat each other, such as one who goes to another trader and tells him: Surely, this product is no good, so do not buy it. He says this so that no one competes with him in buying that product, and if others listen to him, he can buy it in order to obtain maximum profits for himself.
Verily, this act of cunning and the like are forbidden, as it is a form of deceiving, which a Muslim with true belief never does.
Indeed, a Muslim does not cheat another Muslim nor does any act which causes harm to him.Indeed, a Muslim does not cheat another Muslim nor does any act which causes harm to him.