Musnad Abu Ya'la al-Mawsili 154:163

Abu Khaythama narrated to us, Ishaq bin ‘Isa narrated to us, he said: Layth narrated to me, he said: Ibn Shihab narrated to me, from ‘Abdullah bin ‘Abdullah bin ‘Umar, from Ibn ‘Umar, from the Messenger of Allah (may Allah bless him and grant him peace), that he said while he was standing upon the pulpit: "Whoever among you comes to the Friday prayer, let him perform ghusl (ritual bath)."