the example under discussion, he says: “By Allah, I did not sell it for eighty; rather, I sold it for one hundred.” Thus, he begins with the negation first, as is customary: clearing comes before adorning, and this is also to rebut the buyer’s claim.
His statement, “Then the buyer swears: ‘I did not buy it for such-and-such; rather, I bought it for such-and-such,’” means that the buyer swears, saying: “By Allah, I did not buy it for one hundred; rather, I bought it for eighty.” Once the mutual oaths have been completed, if neither party accepts the other’s statement, then each of them has the right to rescind the sale.
The apparent meaning of the author’s words is that the seller’s oath must precede the buyer’s. Thus, if the buyer were to begin first, it would not be valid. So, if we tell the seller, “Swear,” and then the buyer swears, the buyer would, in that case, have to swear a second time, because the author says: “The seller swears first.”
The apparent meaning of the author’s words also is that one must combine negation and affirmation: negating what his opponent claims and affirming what he himself claims. This is stipulated so that, through negation, he refutes what his opponent has claimed, and through affirmation, he establishes what he himself claims. Therefore, if he merely negates what his opponent claims and says, “By Allah, I did not sell it for eighty,” this is not sufficient until he also swears to what he himself claims. Likewise, if he confines himself to affirmation alone and says, “By Allah, I sold it for one hundred, and this buyer is lying,” this too is insufficient. Rather, he must say, by way of negation: “I did not sell it for eighty; rather, I sold it for one hundred.” If he were to place the affirmation before the negation and say, “By Allah, I sold it for one hundred, and I did not sell it for eighty,” then according to the author’s wording, this would not be valid. Thus, three matters are necessary:
First: the seller must swear first.
Second: he must combine negation and affirmation.