Musnad Abu Ya'la al-Mawsili 106:31

Ibrahim ibn ‘Ar‘arah ibn al-Barand narrated to us, Isma‘il ibn Aban narrated to us, Mas‘ud ibn Sa‘d narrated to me, from Yazid ibn Abi Ziyad, from ‘Abd al-Rahman ibn Abi Layla, from al-Bara’, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "It is a duty upon the Muslims that they perform ghusl (ritual bathing) on the day of Jumu‘ah."