Musnad Ahmad 33:433

Muhammad ibn Maymun Abu al-Nadr al-Za'farani narrated to us, Ja'far ibn Muhammad narrated to us, from his father, who said: I asked Jabir, "When did the Messenger of Allah, peace and blessings of Allah be upon him, pray Jumu'ah?" He said: "We used to pray it with the Messenger of Allah, peace and blessings of Allah be upon him, then we would return and rest our camels used for drawing water." Ja'far said: "And the resting of the camels used for drawing water is when the sun passes its zenith."