Jurisprudence

1. To sale and purchase intoxicating beverages, non-hunting dogs, pigs, an unslaughtered carcass (as a precaution). Besides, if a permissible use of Najisul Ayn is possible, like, excrement and faeces being converted to manure or fertilisers, its transaction is permitted, but as a precaution, such sale and purchase should be avoided.
2. Sale and purchase of usurped property.
3. As a precaution, it is haraam to sell and purchase those things which are not usually considered to be merchandise, like, the sale and purchase of wild beasts, if it does not involve any substantial gain.
4. Any transaction which involves interest.
5. Sale and purchase of those things which are usually utilised for haraam acts only, like, gambling tools.
6. A transaction which involves fraud or adulteration, like, when one commodity is mixed with another, and it is not possible to detect the adulteration, nor does the seller inform the buyer about it, like, to sell ghee mixed with fat. This act is called cheating (ghish) or adulteration.
   The holy Prophet of Islam (s.a.w.a) said: "If a person makes a deceitful transaction with the Muslims, or puts them to a loss, or cheats them, he is not one of my followers. And when a person cheats his fellow Muslim (i.e. sells him an adulterated commodity), Allah deprives him of Blessings in his livelihood, closes the means of his earnings, and leaves him to himself."

2064. There is no harm in selling a Pak thing which has become najis, but can be made Pak by washing it. And if it cannot be made Pak with water, and its use does not require it to be Pak, like some oils, its sale is permissible. In fact, even if its use requires it to be Pak, if it has substantial halal benefit, its sale is permitted.

2065. If a person wants to sell a najis thing, he should inform the buyer about it, because by not telling him, he might do something contrary to the rule of Shariah. For example, if he sells him najis water which the buyer may require for Wudhu or Ghusl, and to offer his obligatory prayers, or he sells him something which he uses as food or drink - in all such cases, the seller should inform the buyer. Of course, if the seller knows that it is no use informing the buyer who is careless, and does not care about Taharat or Najasat, then it is not necessary to inform.

2066. Although the purchase and sale of najis medicines for internal or external use is permissible, the buyer should be informed about it in situations explained in the foregoing rule no. 2065.

2067. There is no objection to selling or buying the oils which are imported from non-Islamic countries, if it is not known to be najis. And as for the fat which is obtained from a dead animal, if there is a probability that it belongs to an animal which has been slaughtered according to Islamic law, it will be deemed Pak, and its sale and purchase will be permissible, even if it is acquired from a non-Muslim or is a imported from non-Islamic countries. But it is haraam to eat it, and it is necessary for the seller to inform the buyer about the situation, so that he does not commit anything contrary to his religious responsibility.

2068. If a fox, or any other such animal, is not slaughtered according to religious law, or dies a natural death, it is haraam to purchase or sell its hide, as a precaution.

2069. The purchase and sale of hide and skin which is imported from a non-Islamic country, or is bought from a non-Muslim, is permissible provided that one feels strongly that the animal was most probably slaughtered according to Islamic law. And, namaaz with it will be in order.

2070. The fat obtained from a dead animal, and the hide obtained from a Muslim, when one knows that the Muslim has obtained it from a non-Muslim, without investigating whether or not the animal has been slaughtered according to Islamic law, is Pak, and its sale and purchase permissible. But it is not permissible to eat it.

2071. Transaction of intoxicating drinks is haraam and void.

2072. Sale of usurped property is void, and the seller should return to the buyer the money taken from him.

2073. If a buyer is serious about a transaction, but his intention is not to pay the price of the commodity being purchased by him, this intention will not affect the validity of the transaction, though it is absolutely necessary that he should pay the money to the seller.

2074. If a person has purchased a commodity on credit, and wishes to pay its price later from his haraam earning or wealth, the transaction will be valid, but, he will have to pay the amount which he owes from halal property, in order to be absolved of his responsibility.

2075. Purchase and sale of instruments of entertainment like, guitar, lute and harmonium etc., is haraam, and as a precaution, the same rule applies to the small musical instruments made as toys for the children. However, there is no harm in selling and purchasing instruments of common use, like, radio and tape-recorder, provided that it is not intended to use it for haraam purposes.

2076. If a thing which can be used for halal purposes is sold with the intention of putting it to haraam use - for example, if grapes are sold so that wine may be prepared with them, the transaction is haraam, and as a precaution the deal is void. However, if the seller does not sell it with that Niyyat, but only knows that the buyer will prepare wine with the grapes, the transaction will be in order.

2077. Making a human sculpture or that of an animal, is haraam, but there is no harm in purchasing and selling it, though as a precaution, it should be avoided. However, painting human portraits or animals is permissible.

2078. It is haraam to purchase a thing which has been acquired by means of gambling, theft, or a void transaction, and if a person buys such a thing from a seller, he should return it to its original owner.

2079. If a person sells ghee mixed with fat and specifies it, for example, he says: "I am selling 3 kilos of ghee" - the transaction will be void if the quantity of fat is more, to the extent that it cannot be called ghee.
But if the quantity of fat is small, so that it can just be classified as ghee mixed with fat, the transaction will be valid. But the buyer has a right of refusal, based on the deficiency in the quality, and can therefore cancel the deal and ask for refund.

And if ghee and fat are distinct from each other, the deal covering the fat will be void, and the seller will have to refund the price of that fat, and keep the fat for himself.
But in this case also, the buyer has a right of cancelling the transaction of pure ghee which is in it. Where the seller does not say that he is selling a particular thing, and just sells, say, 3 kilos of ghee he possesses, and if it turns out to be ghee mixed with fat, the buyer can return it, and ask for pure ghee.

2080. If a seller sells a commodity which is sold by weight or measurement, at a higher rate against the same commodity, like, if he sells 3 kilos of wheat for 5 kilos of wheat, it is usury and, therefore, haraam. In fact, if one of the two kinds of same commodity is faultless, and the other is defective, or one is superior and the other is inferior, or if their prices differ, and the seller asks for more than the quantity he gives, even then it is usury and haraam.
Hence, if a person gives unbroken copper or brass and takes more of broken copper and brass, or gives a good quality of rice, and asks for more of inferior kind of rice instead, or gives manufactured gold and takes a larger quantity of raw gold, it is usury and haraam.

2081. If the thing, which he asks for in addition, is different from the commodity which he sells, like, if he sells 3 kilos of wheat against 3 kilos of wheat and one dirham cash, even then it is usury and haraam. In fact, if he does not take anything in excess, but imposes the condition that the buyer would render some service to him, it is also usury and haraam.

2082. If the person who is giving less quantity of a commodity, supplements it with some other thing, for example, if he sells 3 kilos of wheat and one handkerchief for 5 kilos of wheat, there is no harm in it, provided that the intention is that the handkerchief is for the excess he is receiving, and also that the transaction is not on credit.
And if both the parties supplement the commodity with something, like 3 kilos of wheat with a handkerchief is sold for 3 1/2 kilos and a handkerchief, there is no objection to it, provided that the intention is that half kilo of wheat with the handkerchief on one side, was given for a handkerchief on the other.

2083. If a person sells something by measuring in meter or yard, like, cloth, or something which is sold by counting like, eggs and walnuts, and asks for more instead, there is no objection, except when the commodity exchanged are of the same kind and the transaction is on credit, then it is not permissible. For example, if he gives ten eggs on a condition that he should receive eleven eggs after a month, it is a void and haraam transaction.
In matters of the currency notes, a person can sell one type of it for another, like toman against dinar or dollar, on credit, and on condition to receive more. But if he sells toman for toman, expecting more, then that transaction should not be on credit; otherwise it will be void and haraam. For example, if a person gives 100 toman cash, on a condition that after six months he should be given 110 toman, that is void and haraam.

2084. If a commodity is sold in most of the cities by weight or measurement, and in some cities by counting, there is no objection if that commodity is sold against the same commodity at a higher rate, in the city where it is sold by counting. Similarly, if the cities are different, and if it cannot be said that the majority of the cities sell the commodity by weight or measurement or by counting, every city will be governed by the custom prevailing in it.

2085. In commodities which are sold by weight or measurement, if a person sells a commodity in exchange of something which does not belong to the same category, and if the deal is not on credit, he can take more. But if it is on credit, it is not permissible. Hence, if he sells one kilo of rice for two kilos of wheat on a month's credit, that transaction is void.

2086. If a ripe fruit is exchanged for the raw fruit of the same type, one cannot take more. And Fuqaha have commonly held that if a commodity taken in exchange is from the same origin, one should not take more. For example, if someone sells one kilo of ghee made from cow milk for one and half kilos of cheese made from cow milk, it will be usury and therefore haraam. But this generalisation is a matter of Ishkal.

2087. From the point of usury, wheat and barley are commodities of one and the same category. Hence, if a person gives 3 kilos of wheat and takes in exchange thereof, 31/2 kilos of barley, it is usury and haraam. And if, a person purchases 30 kilos of barley, on the condition that he would give in exchange 30 kilos of wheat at the time of its harvest, it is haraam, because he has taken barley on the spot and will give wheat some time later, and this amounts to taking something in excess, and therefore haraam.

2088. Father and son, husband and wife can take interest from each other. Similarly, a Muslim can take interest from a non-Muslim who is not under protection of Islam. But a transaction involving interest with a non-Muslim who is under protection of Islam, is haraam. But after the transaction is completed, and the deal is closed, if payment of interest is permissible in the religion of that non-Muslim, a Muslim can receive interest from him.