Narrated Abu Huraira: Allah's Apostle said "We are the last (to come amongst the nations) but (will be) the foremost on the Day of Resurrection. They were given the Holy Scripture before us and we were given the Quran after them. And this was the day (Friday) about which they differed and Allah gave us the guidance (for that). So tomorrow (i.e. Saturday) is the Jews' (day), and the day after tomorrow (i.e. Sunday) is the Christians'." The Prophet (p.b.u.h) remained silent (for a while) and then said, "It is obligatory for every Muslim that he should take a bath once in seven days, when he should wash his head and body."