Transactions
It is obligatory upon every Muslim to learn the rules of business transactions to the extent of his need. It is obligatory upon the scholars ('Ulamaa’) to teach these rules to the people.
To earn, work, labor and strive in the way of business, agriculture and vocation and things similar to that is obligatory upon he who does not possess the expenses (of maintenance) of his wife and children. Likewise, it is obligatory to preserve the order of Islamic society and secure its needs. In other than these situations, earning and labor is emphatically recommended, in particular, to assist the poor and for the comfort of dependents.
It is recommended that the seller make no distinction between buyers in the price of a commodity nor be difficult nor swear (an oath). When the buyer regrets (the purchase) and seeks to cancel the transaction, (the seller should) accept the cancellation.
Disliked (Makrooh) Business
Relations
Most Jurist (Fuqahaa’) hold the opinion in the dislike of the business transactions which will be mentioned and the best thing is to avoid them:
Money Changing (Suraafah) and all that involves people with the consumption of interest and its activities or miscellaneous unlawful activities.
Selling Shrouds (Kafan) in the situation of it being an established occupation and profession in itself.
Business dealings with the vile people and the owner of doubtful properties in their affairs although the properties are apparently lawful.
Execution of business transactions between the beginning of Fajr and sunrise.
When someone has come forward to buy something and before the transaction is complete, it is necessary that someone else does not interfere in this transaction. This is what is termed as someone interfering in bartering and it is one of the disliked acts.
Unlawful and Invalid
Transactions
Transactions in the following instances are invalid:
Selling and purchase of a source of Najaasah (Aynun-Najaasah). Intended by Najaasah is whatever is inherently Najis (impure), according to obligatory precaution (like urine, stool and blood). Based on this, the selling and buying of fertilizer is objectionable. However, there is nothing preventing benefiting from it. As for the sale of blood and purchase of blood in our times, which is used to save the injured and sick, then, it is permissible. Likewise is the sale of guard dogs and hunting dogs.
The sale and purchase of usurped things except when its owner has endorsed the transaction.
The sale and purchase of things that have unlawful advantage like the instruments of gambling and similar examples.
The sale and purchase of something that has no value in the common perception although it may possess a value with specific individuals, like many insects.
Transactions in which there is interest (Ribaa).
The sale and purchase of counterfeited and adulterated commodities when the purchaser is unaware of its state, like selling milk mixed with water or oil mixed with fat or something else. This action is called cheating (Ghashsh) and it is a major sin.
It has been reported that the Messenger of Allah, Blessings be upon him and his family said: “He who cheats a Muslim or harms him or deceives him is not from us.”
There is no objection in selling the Mutanajjis (commodity). The Mutanajjis commodity is that which has contacted Najaasah (impurity) and it is possible to purify it or use it, like fruits, fabric and carpets. However, when the purchaser intends to use it for eating, or acts that have purity (Tahaarah) conditional for them, it is obligatory to inform (the purchaser) to avoid it.
When something pure becomes impure with that which it is not possible to purify, like oil, if it is used only for eating, then, its sale is invalid and unlawful. As for when it has other uses not having purity condition in them, then, its sale is proper (like impure petroleum).
Edible commodities and its likeness imported from non-Islamic countries, when their impurity is not certain and incontestable, there is not objection in their sale and purchase. Like when it is likely that milk and cheese and oil is prepared and produced by means of an automated process without hands being entered into it.
The sale and purchase of meats and fats supplied from non-Islamic lands or taken from the hand of a non-Muslim is invalid. Likewise are hides (leathers) according to precaution. However, there is no objection when it is known that it is from animals slaughtered in a legal manner or under the supervision of Muslims.
There is no objection in selling and purchasing meats and fats taken from the hand of Muslims. However, when it is known that the Muslim has taken from the hand of a non-Muslim or it is supplied from a non-Muslim country and he has not investigated the method of its slaughter whether it is slaughtered in a legal manner or not, then, its sale and purchase is invalid and unlawful (the ruling of hides is as such, according to precaution). When it is taken from a Muslim, its appearance indicating upon his restriction and obligation to the law, or it is likely that he has investigated it, then, the transaction is proper.
The sale and purchase of all types of intoxicants is unlawful and invalid.
The sale and purchase of usurped (Ghasbi) property is unlawful and invalid. It is obligatory upon the seller to return the price to the purchaser. However, it is not correct that the purchaser should return that usurped thing to other than its owner. When he does not know its owner it is obligatory that he act in accordance with the view of the Religious Authority and his opinion.
When it was the intent of the purchaser from the beginning not to pay the price of the commodity which he has purchased, there is an objection (to this transaction). Likewise it is when (the purchaser's) initial intention was to pay the amount in unlawful money. However, when this was not his intention initially and he only gave the price of the commodity from unlawful property afterward, the transaction is proper, however, it is obligatory that he gives (the price) from lawful property a second time.
The sale and purchase of instruments of entertainment (Lahw), amusement (La'b) and corruption is unlawful and invalid except that it be an instrument shared (between lawful and unlawful) or a instrument of exercise and similar things to that, then, its sale is permitted.