The Messenger of Allah ﷺ said, "Every Muslim man must take a bath one day out of every seven, and that day is Friday."
أخبرنا حميد بن مسعدة قال حدثنا بشر قال حدثنا داود بن أبي هند عن أبي الزبير
قال رسول الله ﷺ على كل رجل مسلم في كل سبعة أيام غسل يوم وهو يوم الجمعة
Sahih. Ahmad reported it, 3/304, from Bishr bin Mufaddal with this chain, and it is in Kubra, hadith 1669. Ibn Khuzayma graded it sahih, hadith 1747, as did Ibn Hibban, hadith 558.Abu Zubayr used an ambiguous form of transmission, but the hadith has very many corroborating narrations in Bukhari, hadith 897, and Muslim, hadith 849, and others besides them.