- If its change disappears on its own.
Or if some of it is drawn off, leaving behind a large quantity that has not changed, it becomes pure …
His statement, “Or if some of it is drawn off, leaving behind a large quantity that has not changed, it becomes pure,” refers to the third method of purifying impure water: water is drawn off until what remains after drawing it off is a large quantity of tahur water.
The pronoun in his statement, “from it,” refers to the large quantity of water, while the pronoun in “after it” refers to the drawing off.
In this case, the water that has become impure must exceed two qullahs, because the author stipulates that a large quantity must remain after drawing it off—that is, two qullahs or more.
Thus, if a person has a vessel containing four qullahs of impure water, and some of it is drawn off until two qullahs remain, and this remainder has undergone no change, it is tahur.
In summary, any amount exceeding two qullahs may be purified in three ways:
- By addition, as mentioned above.
- By its change disappearing on its own.
- By drawing some of it off, leaving behind a large quantity that has not changed.
The correct view is that whenever the change in impure water disappears, it becomes pure, by whatever means this occurs.
His statement, “other than soil and the like”: the author excludes these from the case of addition. Thus, if we add soil, and through its mixing with the water and settling, the impurity disappears, it does not become pure, even though soil is one of the two means of purification. They said: because purification