Musnad Ahmad 33:519

Yunus narrated to us, Abd al-Aziz ibn Abd Allah ibn Abi Salamah narrated to us, from Muhammad ibn al-Munkadir, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Every prophet has a disciple (hawari), and my disciple is al-Zubayr." I heard Sufyan ibn Uyaynah saying: The disciple (al-hawari) means: the helper (al-nasir).