The Prophet ﷺ said, "It is a right Allah has upon every Muslim that he bathe once every seven days, washing his head and his body."
عن النبي ﷺ قال: حق الله على كل مسلم أن يغتسل في كل سبعة أيام، يغسل رأسه وجسده.
Muslim narrated it in the Book of Friday Prayer (849) from Muhammad bin Hatim, who said, Bahz narrated to us, who said, Wahib narrated to us, who said, Abdullah bin Tawus narrated to us, from his father, from Abu Hurairah, and he related the hadith.Bukhari narrated it (896) in a longer version from Muslim bin Ibrahim, who said, Wahib narrated to us with his chain of transmission, and its beginning in his version is, "We are the last, yet we will be the first on the Day of Resurrection. They were given the Scripture before us, and we were given it after them. This is the day about which they differed, and Allah guided us to it. So tomorrow belongs to the Jews, and the day after tomorrow to the Christians." Then he paused, and said, "It is incumbent upon every Muslim to perform ghusl..." and he related the rest as before.His statement, "Then he paused," meaning the Prophet ﷺ that the second sentence is also a statement attributed to him, as evidenced by what Bukhari narrated in the Book of the Prophets (3486), where the phrase "Then he paused" does not appear.