For this reason, it is not legislated except when evidence is impossible to obtain. A substitute is invalidated by the ability to use the original, just as Tayammum (dry ablution) is invalidated by the ability to obtain water. Conversely, the original is not invalidated by the ability to use the substitute. What indicates the difference between the two is that when they are both present and it is possible to hear both, the evidence is heard and judgment is rendered based upon it, while the oath is not heard and is not asked for.

Section: If the claimant requests the imprisonment of the defendant or the provision of a guarantor until his distant evidence arrives, this shall not be accepted from him, and he has no right to hold his adversary in custody. Ahmad explicitly stated this because no right has been proven against him for which he could be imprisoned, nor is he required to provide a guarantor. Furthermore, imprisonment is a form of punishment, and it is not imposed on an innocent person against whom no right has been established. Moreover, if this were permitted, every oppressor would be able to imprison whomever he wished among the people without any right. If his evidence is nearby, he has the right to hold him in custody until he produces it, because that is a necessity for presenting the evidence. If he were not able to hold him, he would leave the judge's assembly, and it would be impossible to present it without his presence. Also, since he is able to bring him to the judge's assembly to present evidence against him, he is able to hold him there until the evidence arrives. This differs from distant evidence or evidence that cannot be present, for compelling him to stay until it arrives requires imprisonment or something that serves its function, and there is no way to do that.

Section: If the claimant presents a single witness and does not swear along with him, and he requests the oath of the defendant, he (the defendant) is made to swear for him. Then, if he produces another witness after that, his evidence is complete, and judgment is rendered by it, for the same reason we mentioned in the preceding case. If the claimant says, "I have evidence present, but I want to make the defendant swear, then I will present the evidence against him," there are two views regarding this. One is that he may do so, and he may demand that his adversary take an oath because he has the right to demand an oath from him if his evidence were distant; therefore, the same applies if it is nearby. Also, if he said, "I do not wish to present my nearby evidence," he would be entitled to demand an oath from him, so the same applies if he does wish to present it. The second view is that he is not entitled to demand an oath from him because evidence is sufficient to replace the oath, so it is not legislated to use it alongside it. Furthermore, evidence is the fundamental principle and the oath is a substitute; thus, one should not combine the substitute and the original, like Tayammum alongside water. This differs from the case of distant evidence, for that is in effect as if it were non-existent due to the inability to access it; the same applies to evidence he does not wish to present, because there might be a hardship for him in bringing it or a hardship for the witness in attending, so that requirement is dropped due to hardship, unlike the case where he does wish to present it.