Abu Huraira reported: The Messenger of Allah, peace be upon him, said,

Abu Huraira reported: The Messenger of Allah, peace be upon him, said, “We are the last nation but the foremost on the Day of Resurrection. They were given scriptures before us and we were given scripture after them; and the day of Friday was the day about which they differed and Allah guided us to it; so tomorrow is for the Jews and the day after tomorrow for the Christians.” The Prophet remained silent for a while and then he said, “It is an obligation upon every Muslim to take a bath at least once every seven days, in which he should wash his head and his body.”

In another narration, the Prophet said, “It is the right of Allah upon every Muslim that he takes a bath at least once every seven days.”

[Sahih Bukhari, Book 13, Number 21]

عَنْ أَبِي هُرَيْرَةَ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَحْنُ الْآخِرُونَ السَّابِقُونَ يَوْمَ الْقِيَامَةِ أُوتُوا الْكِتَابَ مِنْ قَبْلِنَا وَأُوتِينَاهُ مِنْ بَعْدِهِمْ فَهَذَا الْيَوْمُ الَّذِي اخْتَلَفُوا فِيهِ فَهَدَانَا اللَّهُ فَغَدًا لِلْيَهُودِ وَبَعْدَ غَدٍ لِلنَّصَارَى فَسَكَتَ ثُمَّ قَالَ حَقٌّ عَلَى كُلِّ مُسْلِمٍ أَنْ يَغْتَسِلَ فِي كُلِّ سَبْعَةِ أَيَّامٍ يَوْمًا يَغْسِلُ فِيهِ رَأْسَهُ وَجَسَدَهُ

رَوَاهُ قَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لِلَّهِ تَعَالَى عَلَى كُلِّ مُسْلِمٍ حَقٌّ أَنْ يَغْتَسِلَ فِي كُلِّ سَبْعَةِ أَيَّامٍ يَوْمًا

856 صحيح البخاري كِتَاب الْجُمُعَةِ غسل يوم الجمعة واجب على كل محتلم