According to them, the two “ankles” are the point where the sandal-straps are fastened—the joint between the foot and the heel, which they call the “arch of the foot.” In the view of Ahl al-Sunnah wal-Jamaʿah, however, the intended ankles are the two protruding bones at the bottom of the shin where the leg meets the foot. Hence, wiping the feet is invalid, because the best-known recitation of the verse places “your feet” in the accusative, conjoining it with the limbs that must be washed—“your faces and your hands” (Al-Māʾidah 6). The limb that is to be wiped—the head—was inserted between the washed limbs to indicate the required sequence; had it been mentioned after the feet, one might assume that wiping the head comes after washing the feet.
As for the genitive reading, “and your feet,” it is sound, but it can be answered in four ways. First, the genitive here is due to proximity (majāwarah), a recognized Arabic usage. One may say, for example, “This is a dilapidated lizard hole,” where “dilapidated” describes the hole, not the lizard, even though “hole” is nominative; the adjective is rendered genitive simply because of its closeness to “lizard” and for ease of pronunciation.
Second, what is meant by “wipe” here is actually “wash,” for washing is sometimes called wiping. One may say, “I wiped myself with water,” meaning, “I washed with it.” Thus, “wiping the feet” in this verse means washing them, as confirmed by the accusative reading.