It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The millstone of Islam will turn at the head of thirty-five, thirty-six or thirty-seven (years). If they (the people) perish, then (they will follow) the way of those who perished; and if they remain, they will remain for seventy years."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10318