purification, for Allah Himself has described it in these terms, as He says, “And He sends down upon you water from the sky so that He may purify you with it” (Q 8:11).

The impurity that must be removed may either be on the surface of the ground and what is connected to it—such as walls, basins, or rocks. In that case, a single washing that eliminates the very substance of the impurity is sufficient. Practically, the spot is purified by drenching it with water once, for the Prophet ﷺ ordered that water be poured over the Bedouin’s urine that he passed in the mosque. The same holds true if the spot is flooded by rainfall or runoff; once the impurity disappears through a single pour or through descending or flowing rainwater, that alone suffices for its purification.

If, however, the impurity is on something other than the ground and what is attached to it, and it comes from a dog, a pig, or anything born of either of them, then it must be washed seven times, one of which with earth—soil is mixed with one of the washes—because the Prophet ﷺ said, “When a dog licks the vessel of any one of you, let him wash it seven times, the first of them with earth,” related by Muslim and others. This ruling is general: it applies not only to vessels but equally to garments, bedding, and the like.