and their sweat, if it is a small amount. This is the manifest view from Ahmad. Al-Khallal said: 'And upon this is the school of Abu 'Abd Allah, because it is difficult to avoid it.' Ahmad said: 'Who is safe from this among those who ride donkeys! Except that I hope that what is light of it is easier.' Al-Qadi said: 'The same applies to what shares their meaning among predatory beasts, other than the dog and the swine, and the same ruling applies to their urine and dung, as well as the urine of the bat.' Al-Sha'bi, al-Hakim, Hammad, and Habib ibn Abi Thabit said: 'There is no harm in the urine of bats.' Likewise the bat itself, because it is difficult to avoid it, for it is abundant in mosques; if its small amount were not excused, it would not be possible to remain in mosques. The same applies to the urine of animals whose meat is eaten, if we say it is impure, because it is difficult to avoid it due to its frequency. Another narration from Ahmad states: 'No small amount of any of that is excused,' because the original principle is that no impurity is excused, except what was exempted regarding blood and what is generated from it, so all else remains upon the original principle.

Section: Heavy impurities are exempted due to their location in three instances. The first of these is the location of cleaning (istinja'). It is excused regarding the traces of using stones (istijmar) after cleaning and completing the required number, without any disagreement that we know of. Our companions differed regarding its purity. Abu 'Abd Allah ibn Hamid and Abu Hafs ibn al-Muslim went to the view of its purity. This is the apparent meaning of Ahmad's words, for he said regarding one who uses stones and sweats in his trousers: 'There is no harm in it.' If it were impure, he would have rendered it impure. The basis for this is the saying of the Prophet, peace and blessings of Allah be upon him, regarding dung and bones: 'They do not purify.' The implication is that things other than them do purify, and because it is a means that removes the ruling of the impurity, thus it removes it just like water. Our later companions said: 'The location is not purified; rather, it remains impure. If one who performed istijmar sat in a small amount of water, he would make it impure, and if he sweated, his sweat would be impure, because wiping does not remove all parts of the impurity, so what remains of it is impure, because it is the essence of the impurity, thus it resembles what would be if it were found in the location by itself.' The second instance is the bottom of the leather sock (khuff) and footwear.