Mura traced it back to the Prophet ﷺ, who said regarding the ghusl on Friday, "It is obligatory upon every male who has reached puberty."
حدثنا سفيان عن صفوان بن سليم عن عطاء بن يسار
مرة يبلغ به النبي ﷺ قال الغسل يوم الجمعة قال هو واجب على كل محتلم
Its isnad is sahih. Safwan bin Salim is a trustworthy imam. The hadith is found in Bukhari 1/217, in the chapter on adhan, and on children performing wudu, and in Muslim 2/580, number 846.