Musnad Abu Ya'la al-Mawsili 251:1

Abu Kurayb narrated to us, Mu'awiyah narrated to us, from Shayban, from Jabir, from 'Amir, from Jarir, who said: I heard the Messenger of Allah (may Allah bless him and grant him peace) saying: "Islam is built upon five: the testimony that there is no god but Allah, the establishment of prayer, the giving of zakat, the pilgrimage to the House, and the fasting of Ramadan."