The wounded person knows that the tayammum is a substitute for washing the wound, while the one who lacks sufficient water for all of his limbs does not know the amount for which he must perform tayammum until after he has used the water and exhausted it, so it became mandatory for him to use it first. If the wounded person is purifying himself for a minor impurity (hadath asghar), al-Qadi mentioned that he is obligated to maintain the order (tartib), so he places the tayammum in the place of the [act of] washing for which the tayammum is a substitute. If the wound is on his face in such a way that he cannot wash any part of it, he is obligated to perform tayammum first, then perform tayammum for the wudu. If it is on a part of his face, he is given the choice between washing the healthy part of his face then performing tayammum, or performing tayammum then washing the healthy part of his face and completing his wudu. If the wound is on another limb, he is obligated to wash what precedes it, and then the same ruling applies as what we mentioned regarding the face. If it is on his face, hands, and feet, he requires a tayammum for each limb at the place of its washing in order to achieve the order. If he were to wash the healthy part of his face, then perform one tayammum for it and for his hands, it would not suffice him, because this leads to the dropping of the obligation from a part of the face and the hands at one time. If it is said: This is invalidated by the tayammum for the entire purification, where the obligation drops from all the limbs at once. We say: If it is for the entire purification, the ruling is for it rather than the limbs [individually], but if it is for some of them, it acts as a substitute for that specific part; therefore, what is considered for what it replaces—in terms of order—is considered for it. It is possible that this order is not mandatory, because tayammum is an independent purification, so the order is not required between it and other purification, just as if the wounded person were junub. Also, because he is performing tayammum for a minor impurity, it is not mandatory to perform tayammum for every limb at the place of its washing, as if he performed tayammum for the entirety of the wudu. Furthermore, there is hardship and harm in this, which is repelled by His saying (the Almighty): "And He has not placed upon you in the religion any difficulty" [Al-Hajj: 78]. Al-Mawardi narrated this from the school of al-Shafi'i, while Ibn al-Sabbagh narrated from him [a view] like the first opinion.