مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 539
Purification
Washing as Established by the Sunna - Section 1
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «حَقُّ عَلَى كُلِّ مُسْلِمٍ أَنْ يَغْتَسِلَ فِي كُلِّ سَبْعَةِ أَيَّامٍ يَوْمًا يَغْسِلُ فِيهِ رَأسه وَجَسَده»
Abu Huraira reported God’s messenger as saying, “It is a duty for every Muslim to bathe once a week, washing his head and his body.” (Bukhari and Muslim.)
Mishkat al-Masabih, 539مُتَّفَقٌ عَلَيْهِ (الألباني)