Volume 4, Book 56, Number 693:
Narrated Abu Huraira:
The Prophet said, “We are the last (to come) but we will be the foremost on the Day of Resurrec –
tion, nations were given the Book (i.e. Scripture) before us, and we were given the Holy Book after
them. This (i.e. Friday) is the day about which they differed. So the next day (i.e. Saturday) was pre –
scribed for the Jews and the day after it (i.e. Sunday) for the Christians. It is incumbent on every
Muslim to wash his head and body on a Day (i.e. Friday) (at least) in every seven days.”