Musnad Abu Ya'la al-Mawsili 108:29

'Abd al-A'la narrated to us, Ya'qub ibn 'Abd Allah narrated to us, from 'Isa ibn Jariyah, from Jabir ibn 'Abd Allah, who said: The Messenger of Allah (may Allah bless him and grant him peace) went out in Makkah and passed by a man standing, praying upon a rock. He then went to a side of Makkah and stayed for a while. Then he returned and found the man in his state, praying. He joined his hands together, then said three times: "O people, you must be moderate, you must be moderate, you must be moderate. For Allah will not grow weary until you grow weary."