and qabil (surety), and kafil (guarantor), and za'im (leader/surety), and sabir (surety), are all one in meaning. The totality of this is that a sale with the condition of a pledge or a guarantor is valid, and the condition is likewise valid, because it is among the interests of the contract and does not contradict its requirements. We are not aware of any disagreement regarding its validity if it is known. For this reason, Al-Khiraqi said: "that they both know" regarding both the pledge and the guarantor. Knowledge of the pledge is achieved by one of two things: direct observation, or a description by which the described object is known, as in a salam sale. It is determined by taking possession. As for the guarantor, he is known by pointing to him or by defining him by name and lineage. It is not valid by description alone, such as saying: "a rich man," without specification, because the description does not apply to him [specifically]. If he said: "on the condition of a pledge or a guarantor" [without specifying which], it would be void, because these vary and have no custom to which one might refer without qualification. If he said: "on the condition of pledging one of these two slaves" or "that one of these two men acts as my guarantor," it is not valid, because the purpose varies, so it is not valid without specification, just as in a sale. This is the school of Al-Shafi'i. It is narrated from Malik and Abu Thawr that the condition of an unknown pledge is valid, and he is obligated to pay him a pledge equal to the debt, because it is a security (wathiqah), so stipulating it absolutely is permissible, like testimony. Abu Hanifa said: If he said: "on the condition that I pledge to you one of these two slaves," it is permissible, because his sale is valid according to him. Our position is that he stipulated an unknown pledge, so it is not valid, just as if he stipulated pledging what is in his sleeve. Furthermore, it is a contract in which the object of the contract varies, so it is not valid with ignorance, like a sale. It differs from testimony, as that has a known convention in Islamic law upon which it is based. The discussion with Abu Hanifa has already passed regarding the sale, for the disagreement in both is one and the same. Once this is established, if the buyer fulfills the condition by delivering the pledge, or if the guarantor guarantees on his behalf, the sale becomes binding. If he refuses to deliver the pledge, or the guarantor refuses to guarantee on his behalf, the seller has the choice between annulling the sale or completing it and accepting it without a pledge or a guarantor. If he agrees to it, the sale becomes binding upon him. This is the position of Al-Shafi'i and the scholars of opinion (Ashab al-Ra'y). The buyer is not forced to deliver the pledge. Malik and Abu Thawr said: The pledge is binding if