2146. If a person gives a commodity to another person, and fixes its price and says: "Sell this commodity at this price, and the more you sell, you will be paid your commission." If he sells the commodity for higher price, the excess of money realised will be that of the owner, and he will be entitled only to the commission from the owner.
But if the arrangement is by way of granting a reward, when the owner says: "If you sell this commodity at a price higher than that, the excess of proceeds will be your property" there is no harm in it.
2147. If a butcher sells the meat of a female animal saying that it is the meat of a male animal, he commits a sin. Hence, if he falsely specifies the meat saying: "I am selling this meat of a male animal" the buyer can cancel the transaction. And in case, he does not specify it, the butcher must supply the meat of a male animal, if the buyer is not willing to accept the meat which has been given to him.
2148. If a buyer tells the draper that he wants a cloth of fast colour, and the draper sells him a cloth whose colour fades, the buyer can cancel the transaction.
2149. Swearing in the matter of transaction is Makrooh, if it is true, and haraam, if it is false.