When is the oath directed at the claimant?

Question : The oath is not directed at the claimant unless his evidence is not present.

Answer : If the claimant's evidence is present, we are in no need of it. Yes, we are in no need of it. But if the defendant claims, for example, that he has paid the right, meaning that the claimant has presented evidence that he has one hundred riyals with so-and-so, and he has presented evidence, but the one against whom the one hundred riyals were established claims that he has paid them, and this happens often: the right is established by witnesses, then the debtor pays the creditor without evidence, and then the owner of the right comes and claims against him, presenting whom? He presents the previous evidence. What is the judge's position here? His position is to rule based on the evidence and say to the creditor, who is the defendant: You are the one who was negligent. Why did you not present evidence for your payment of the right? And what concern is it to me other than the apparent? Do we say in this case that the claimant swears that the owner of the right has not paid him? This is also a matter of disagreement among judges, among the scholars of the past. Some of them had the claimant swear, and some of them had the claimant swear due to the possibility that the defendant is truthful. Do you understand the situation well, or not?
Fine, and some of them did not have him swear, saying: This man presented evidence that such and such was established for him with so-and-so, so we rule based on the evidence. The possibility that so-and-so paid what was due to him is a possibility, but the negligence is on the one against whom it was established. Why did he not present evidence for its payment? Especially if it was established against him by evidence, it is negligence to return it without evidence.