Maliks Muwatta Book 005, Hadith Number 004.

Section : Doing Ghusl on the Day of Jumua.

Yahya related to me from Malik from Safwan ibn Sulaym from Ata ibn Yasar from Abu Said al-Khudri that the Messenger of Allah, may Allah bless him and grant him peace, said, "Ghusl on the day of jumua is incumbent on every male who has reached puberty."