Musnad Ahmad 26:183

'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 at thirty-five, or thirty-six, or thirty-seven. If they perish, then it is the path of those who have perished. And if their religion stands firm for them, it will stand for them for seventy years." He (the narrator) said: I said: "Is that from what has passed or from what remains?" He said: "From what remains."