Musnad Abu Ya'la al-Mawsili 152:213

Abu Khaythama narrated to us, Abd al-Rahman narrated to us, from Sufyan, from Mansur, from Rib'i, from al-Bara' ibn Najiyah, from Abdullah, from the Prophet (peace and blessings of Allah be upon him), who said: "The millstone of Islam will revolve for thirty-five, thirty-six, or thirty-seven [years]. If they perish, then it is the path of those who perished. And if their religion is established for them, it will be established for them for seventy years." I said, "From what has passed or from what remains?" He said, "From what remains."