Musannaf Ibn Abi Shayba 3:2643

Muhammad ibn Bishr and Ibn Fudayl narrated to us, they said: Mis'ar narrated to us, from Wabarah, from Hammam ibn al-Harith, who said: Abdullah said: "Indeed, from the Sunnah is performing ghusl (ritual bathing) on the day of Jumu'ah."