Is it permissible to wipe over a head covering (Imamah) after performing ablution involving wiping over socks (Khuff) previously, or vice versa?
Chapter on Wiping over the Khuffayn (Leather Socks)
Al-Mughni
Book of Purification
Primary text
Some of our companions maintain that wiping over the head covering (Imamah) after performing ablution where wiping over socks (Khuff) was done, or wiping over the socks after wiping over the head covering, is not permissible. This is inferred from the apparent statement of Ahmad, because the wiping was performed upon a state of purity that itself involved wiping over a substitute (the socks or the head covering). Therefore, wiping over the second item is not validly established through this act of wearing, similar to wearing one pair of socks over another pair already wiped over.
Supporting text
The view of Al-Qadi suggests that wiping may be permissible in this situation because the prior ablution involving wiping over a substitute is considered a complete purification. Furthermore, neither the sock nor the head covering is considered a substitute for the other, unlike the case where one pair of socks is worn over another pair that was wiped over.