is abundant, it is deemed purifying.
“Abundant” refers to roughly two qullahs,1 while anything less is classed as a small amount. The two qullahs equal five hundred ratls by the Iraqi measure, and eighty ratls, two-sevenths, and half of a seventh by the Jerusalem measure. In terms of volume, the two qullahs fill a cube measuring a cubit and a quarter in length, width, and depth.
Whenever ṭahūr (purifying) water2 is abundant and its characteristics have not been altered by the impurity, it remains purifying even though the impurity is still present. If one is unsure whether the quantity reaches the level of abundance, it is treated as impure.
If water that may be used for ritual purification becomes mixed up with water that may not be used, one does not attempt to choose between them; rather, one performs tayammum (dry ablution) and pours none of the water away.
Anyone who knows that something is impure is obliged to inform whoever intends to use it.
1 Two large earthenware jars traditionally used as a legal measure.
2 I.e., water that can itself lift ritual impurity.
(1) The phrase in question should follow his words, “and they are five hundred Iraqi ratls,” because the legal definition of “a large amount” is precisely two qullahs. If the volume falls slightly short of two qullahs, it is no longer deemed such, for the ruling hinges on whether the water reaches the measure of two qullahs or not. The statement that two qullahs equal five hundred Iraqi ratls is only an approximation, not an exact figure; a shortfall of one or two ratls is inconsequential, and the quantity is still called “two qullahs,” since the measure is established by textual evidence. The two qullahs referred to are the jars of Hajar: one qullah holds two water-skins (qirbah) and a little extra. A single qirbah holds one hundred ratls. The jurists, out of caution, treated the “little extra” as half a qirbah, although it could in fact be less than half, even as little as a quarter. Hence they tolerated a slight deficiency in the calculated total. This point is self-evident and needs no further deliberation. (Hashiyat al-Labadi, p. 13)
(2) The words “wa-l-tahur” are absent from manuscript “N.”