He says: "I did not permit you except to buy something else." Or he says: "I bought it for you for two thousand." The principal says: "I did not permit you to buy it except for one thousand." In this case, the word is that of the principal, and he is required to take an oath. Once he swears, he is absolved of the purchase. Then, there are two possibilities: either the purchase was made with the specific property itself or on credit (in the dhimma). If it was with the specific property, the sale is void, and the slave girl is returned to the seller if he acknowledges that. However, if the seller refutes him regarding the claim that the purchase was for someone else or with someone else's property without his permission, then the word is that of the seller, because the manifest appearance is that what is in a person's possession belongs to him. If the agent claims that the seller knew of this, he shall make him swear that he does not know that he bought it with his principal's property; because he is swearing to the negation of another's action, his oath is thus regarding the negation of knowledge. Once he swears, the sale is upheld, and the agent is liable for the price to his principal and must deliver the price to the seller. The slave girl remains in his possession, but he cannot treat her as lawful (istihlal); because he cannot be certain whether he is truthful—in which case she belongs to the principal—or whether he is lying—in which case she belongs to the seller. If he wishes to make her lawful, he buys her from whom she belongs to in reality. If he refuses to sell her to him, he refers the matter to the ruler so that he may gently urge him to sell her to him, so that ownership is established for him in appearance and in reality, and that which was established as a debt in his dhimma becomes a set-off against what the other took from him unjustly. If the other refuses to sell, he is not compelled to do so, because it is a contract of mutual consent. If he says: "If the slave girl is mine, then I have sold her to you," or the principal says: "If I permitted you to buy her for two thousand, then I have sold her to you," there are two views regarding this: The first is that it is not valid. This is the opinion of al-Qadi and some of the Shafi'is, because it is a sale suspended on a condition. The second is that it is valid; because this is a realized matter that both know to be present, so making it a condition causes no harm, just as if he were to say: "If this slave girl is my slave girl, I have sold her to you." This applies to every condition that both know exists, for it does not cause the sale to be suspended or create doubt therein. As for if the agent purchased it on credit (in the dhimma) and then paid the price, the purchase is valid and binding upon the agent in appearance. In reality, however, if the agent is lying in his claim, the slave girl is his; because he purchased her on his own dhimma without the command of another. If he is truthful, the slave girl belongs to his principal. If he wishes to make her lawful for him, he achieves this by buying her from him, as we have mentioned. And in every instance where she belonged to the principal in reality