Musnad Abu Ya'la al-Mawsili 130:50

Muhammad ibn Abi Bakr al-Muqaddami narrated to us, Mubarak, the freed slave of Abd al-Aziz ibn Suhayb, narrated to us, Abd al-Aziz narrated to us, Anas ibn Malik narrated that the Prophet, peace and blessings of Allah be upon him, had Mu'adh ibn Jabal ride behind him. He said, "O Mu'adh," at the top of his voice. He said, "At your service, Messenger of Allah." Then he called him a second time, then he called him a third time at the top of his voice. He said, "At your service, Messenger of Allah." He said, peace and blessings of Allah be upon him, "Whoever does not associate partners with Allah, for him is Paradise."