Musnad Ahmad 26:828

Ya'qub narrated to us, my father narrated to us, from Salih ibn Kaysan, from al-Harith—I think he means Ibn Fudayl—from Ja'far ibn 'Abd Allah ibn al-Hakam, from 'Abd al-Rahman ibn al-Miswar, from Abu Rafi', from 'Abd Allah ibn Mas'ud, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "There was no prophet whom Allah, the Almighty and Majestic, sent to a nation before me, except that he had disciples from his nation and companions who would follow his Sunnah and emulate his command. Then, there came after them successors who would say what they did not do, and do what they were not commanded to do."