CR (85) According to the well-known view it is necessary for what is sold and what is paid for it, to be such property that for the acquisition of which people of reason are ready to compete with each other. Things that are not of any value like some of the insects, cannot lawfully be sold or paid for a piece of goods, but, apparently, such condition is not necessary, although to consider it necessary is a precautionary rule.

CR (86) The rights in general are like rules as it is not valid to sell them, they cannot be paid for what is purchased also, however, in case they can be transferred it is permissible to assign the object of the right as a payment and it is permissible to receive something in exchange for waiving one's rights in favor of some one even if the right involved is not transferable but could be waived, as it is permissible to assign the waiving as price and payment for some thing like an amount of work which may become the property of the buyer and it becomes necessary for him to waive after selling.

CR (87). For the validity of a contract it is necessary that the deal is not a loss for a party. Such loss can be avoided by observation when observation is commonly needed and the quantity of the goods to be exchanged must properly be measured or weighed and determined to be equivalent of each other. It is not an offense to use weighing instead of measurement and vice verse as long as no loss is caused to one party. In certain cases observation is the way to avoid losses and in other cases by means of finding out the exact quantity and quality. All depends on common practice and forms of doing business.

CR (88) For learning the exact amount and quantity of the merchandise the report of seller is enough as regards its weight, measurement or number, regardless, the seller is a just person or not, according to a precautionary rule the buyer should be satisfied with his report. If a deficiency is discovered that the amount is more than the agreed one, the seller will have the choice to annual or approve the deal for the whole merchandise, it also is said that in the case of deficiency, the buyer asks for compensation and in the case of the extra amount it goes to the seller in the second case, but such view is weak.

CR (89) In the case of properties wherein the size of the area has a bearing on the price it is necessary to know such factor as in the case of fabrics and lands, observation is not enough, unless observation removes losses from the deal as in the case of sale of houses etc.

CR (90) If the practice of localities is different to determine the qualities and quantities of certain merchandise like weighing in one place and measuring or counting in another place, the practice of the location of the deal must be held effective, but dealing according to a different means of determination is also valid if no loss is caused to any one.

CR (91) Sometimes a certain weight is a requirement in the merchandise sold by a measurement or vice verse, like the sale of a ton of oil that is required to be a barrel in size and it is later discovered that it is different because of the heaviness or lightness of the oil and the same thing can take place in the deals of fabrics, when the presence of another quality represents a higher quality of merchandise not a necessary ingredient of the merchandise. In the case of any inconsistencies the buyer has the right of having the choice to approve the deal in which case he pays in full and extra goes to the buyer anyway.

CR (92) It also is necessary for the validity of the contract to know the kinds and qualities of goods to be exchanged, the kinds and qualities that make a difference in the prices, like colors, tastes higher and lower qualities, thick and thinness etc. If it does not affect the price, it is not necessary to know them although they are liked by some people and are not liked by the others; one may know such factors either by observation, the description of the seller or previous observation.

CR (93) It also is necessary for the validity of the contract that the goods to be exchanged are owned (by the parties) as is usual among people or similar to what is owned like a merchandise of general nature for the delivery of payment of which a party is responsible or like a specified property appropriated for a certain cause like the sale of the Zakat property by its custodian or buying food for the animals of Zakat. Thus, it is not permissible to sell anything unlike the above example like selling birds in the sky, fish in the sea or trees of the jungle before securing ownership of such articles.

CR (94) It is lawful for the mortgagor to sell the mortgaged substance by the permission of the mortgagee, the same rule applies if the mortgagee approves the deal after it takes place, according to a more clear reason, the sale is also valid even if the mortgagee does not approve the sale except that the buyer will have the right to revoke the contract if he does not know the situation at the time of the contract.

CR (95) Selling endowed property is unlawful except in the following cases: (a) The property is dilapidated as such that it cannot serve its cause in its existing condition like a slaughtered animal or such other substances.

(b) That it is dilapidated so much such that it does not produce any benefits or such benefits are so little that common sense would consider it of no significance at all.

(c) That the donor has set a condition requiring its sale at the taking place of a certain matter, like the diminishing of its benefits or the increase of taxes on it or that the sale is more beneficial or the beneficiaries need some thing else in exchange for it etc.

(d) That a serious dispute arises among the beneficiaries and because of this there is fear about the loss of property or lives.

(e) That the donor's condition requires the endowed property to remain in a specified form like a garden etc., and such form does no more exist in such case it is lawful to sell it even if the benefits produced are as normal or more. (f) That a situation arises which leads to a deteriorating condition or diminished benefits, the profits acceptable according to common practice. What is necessary in such case is to delay the sale to the latest possible time to benefit from it.

CR (96) The above cases wherein the sale of the endowed property is lawful, does not apply to the mosque. The sale of mosque is not lawful in all cases. The above rule, however, applies to guesthouses, the books for schools and buildings for public welfare.

CR (97) If the sale of the endowed property for any of the reasons mentioned becomes lawful, if it does not have a supervisor like those endowed in favor of certain individuals besides such beneficiaries other's permission is not required, otherwise, the permission of the supervisor is required and it is necessary to ask him for all matters about the endowed property and if there is no supervisor the case according to a precautionary rule should be presented to the high authority in shari'a to acquire his permission in the matter and also because of a precautionary rule with the money received another property to be endowed for the same cause should be purchased. However if only some parts of the endowed property are dilapidated it is lawful to sell such parts to use the money for the upkeep of the rest or for some other endowed property serving a similar cause. If the endowed property deteriorates and no benefits can be acquired from it, if it is possible to sell some parts of it to repair the rest, according to a precautionary rule the sale should be limited to what is needed for repairs.

CR (98) It is not lawful to sell the Kharaji land; such land is the land forcibly conquered and established at the time of conquest. Such lands belong to Muslims: those existing as well as those to come into existence, regardless, there are the marks of the seller's ownership like buildings or trees etc. In fact, apparently, it is not permissible to use such lands without the permission of the high authority in shari'a, except when it is under the control of a ruler who claims to be Khalifa, in which case it is enough to acquire such ruler's permission in fact, in such a case to consider acquiring the permission of the high authority enough, is objectionable. If the conquered land already established during the conquest is becoming barren, it is not far from reality to own such lands by means of reviving. The land, which is dead at the time of conquest, is the property of IMAM (AS). If any one revives it, it becomes his property because of reviving, regardless, he is a Muslim or a non-Muslim, and he does not have to pay for it anything and if he leaves it until it becomes barren and dead again, it remains his property but if he does not cultivate it and does not benefit from it in any way, it is permissible for others to cultivate it. The second person is the more rightful over it, although according to a preferable precautionary rule it should not be cultivated without his permission if he could be known, unless he has abandoned it. If the ruler who claims to be a Khalifa revives it for the Muslims the rule of the lands of Kharajiyah as explained before applies to it.

CR (99) Specifying the Kharajiyah lands is not free from objection, although the scholars and historians have mentioned numerous pieces of lands as such. If it cannot be found out exactly and one has doubts whether a piece of land was dead at the time of the conquest or established, it will be assumed as dead, thus, it is lawful to revive and own it, as well to sell it etc., such other uses that require ownership.

CR (100) It is necessary for both the merchandise to be exchanged that it could be delivered and possession could be transferred, thus, the sale of a run-away camel or a bird in the air or a fish in the sea is not permissible, regardless, the situation is known or not. If a usurped substance is sold and the buyer is able to get it back from him and then deliver it to him, it is valid. It also is valid to sell it to the usurper even if the seller is not able to get it back from him and then give possession. The same rule applies if the merchandise is such that the buyer is not entitled to own it like buying of a slave who may become free when purchased by the buyer is not able to take possession.

CR (101) If one knows that he is able to deliver and sell the property and then the opposite is discovered, the deal is void; if one knows of his inability to deliver but then the opposite is discovered, apparently, the contract is valid.

CR (102) If one loses control and ability to deliver when delivery is due but knows that he regains such ability later, if the time is just little the deal is valid and if the length of such time is not negligible, if the duration is known like a year or more, apparently, the contract is valid if the buyer knows or even if he does not know but it establishes in favor of the buyer the right of having the choice to annul the contract. If the duration of time is not exactly known, apparently, the deal is void, like selling of an animal which has for the time being disappeared and it is known that the animal will be found but not exactly when.