What is the ruling regarding wiping over the exposed part of the head when wiping over the turban?
Chapter on Wiping over the Khuffayn (Leather Socks)
Al-Mughni
Book of Purification
Primary text
If a part of the head that custom dictates leaving uncovered is exposed while wiping over the turban, it is recommended (mustahabb) to wipe over that exposed area along with the turban. This is explicitly stated by Ahmad, based on the authentic hadith of Al-Mughirah ibn Shu'bah, where the Prophet, peace be upon him, wiped over his turban and his forelock (nasiyah).
Supporting text
There is a difference of opinion on whether combining wiping over the exposed part and the turban is obligatory. Ahmad paused on this issue, resulting in two views: one holds that it is obligatory due to the report and because the turban acts as a substitute for the covered part, leaving the remaining part subject to the original ruling, similar to a splint (Jabeerah). The second view holds that it is not obligatory because the turban substitutes for the entire head, transferring the ruling to it, leaving no ruling for the exposed part; furthermore, obligating both combines a substitute and the substituted item on one limb without necessity, akin to the Khuff.