purely as an exchange contract; thus, knowledge of the subject matter of the contract is a condition for it, just as in a sale. As for the camel driver, he needs to know the passengers and the equipment in which they are riding, such as a litter (mahmil), a mahara, or others; and if it is a miqnab, he must mention it. Also, whether it will be covered or uncovered—if it is covered, the knowledge of the covering is required. He also needs to know the saddle cushion (wita') used to pad the litter, and the hanging items that accompany it, such as a water skin, a water bag, a provision bag, and the like, as well as mentioning all else that he will carry with him. This is the opinion of al-Shafi'i, Abu Thawr, and Ibn al-Mundhir, except that al-Shafi'i said: It is permissible to leave the covering of the litter unspecified because it does not vary in a significantly different way. It was narrated from him regarding the hanging items that it is permissible to leave them unspecified and they are to be interpreted according to custom. It was narrated from Malik that it is permissible to leave the passengers unspecified, because human bodies are generally similar. Abu Hanifa said: If he says, "In the litter are two men and what suffices them of cushions and blankets," it is valid by way of istihsan (juristic preference), because that is similar in custom, so it is interpreted according to custom, like the hanging items. Al-Qadi said regarding the covering of the litter the same as al-Shafi'i's opinion. Our view is that this varies and differs significantly, so knowledge of it is a condition, like the food he carries with him. Their statement that human bodies are similar is incorrect; for among them are the large and the small, the tall and the short, the fat and the thin, the male and the female, and they differ in that regard, varying significantly. They also vary regarding the hanging items, for some increase their provisions and necessities, while others are content with a little, and there is no established custom to refer to regarding this, so knowledge of it is a condition, just like the litter and the cushions. Likewise is the covering of the litter; among people are those who prefer the wide, heavy one which is difficult to carry in the wind, and those who are content with a narrow, light one. Therefore, knowledge of it is obligatory, like the rest of what we have mentioned. As for the lessee, he needs to know the beast he is riding, because the purpose varies thereby, and this is achieved by one of two matters: either by seeing it, which suffices because it is the highest of the ways of knowledge, unless it is of the type that needs