وَامْسَحُوا بِرُءُوسِكُمْ وَأَرْجُلَكُمْ إِلَى الْكَعْبَيْنِ
Meaning: Wipe your heads and wash your feet to the ankles.
The verb wa-msahu applies to the head, and ila al-ka‘bayn states the limit for the feet. This phrasing is central to the legal discussion of wiping, washing, and the prescribed extent.