he wipes while resident and then travels, or travels first and afterwards wipes while resident, he is not granted the full traveller’s allowance. Its validity further depends upon his having put the khuffs on after a complete ablution, that they cover the area whose washing is obligatory, be ritually pure, and be sturdy enough for a traveller to walk in them repeatedly while attending to his needs—some have added: and that they be lawfully acquired. According to the sounder view, a woven covering that does not prevent water from reaching the skin is insufficient, and—on the preponderant opinion—so are two jarmūqs. It is, however, permissible—again on the sounder view—to wipe over a khuff whose foot-portion is split provided it is tightly fastened. The Sunnah is to pass the wet hand over both its upper and lower surfaces in strokes, yet any action that may be called wiping over the area corresponding to the obligatory washing suffices, except for the sole of the foot and the heel; over these no wiping is valid according to the school.
I add: its edge is like its underside, and Allah knows best. One who is unsure whether the time-limit remains may not wipe. If he enters a state of major ritual impurity, he must don the khuffs anew. Whoever removes them while still within the state of purity obtained by wiping must wash his feet, and—in another opinion—perform a full ablution.