Sunan Ibn Majah, Chapter: The Chapters on Tribulations

that the Messenger of Allah (saw) said: that the Messenger of Allah (saw) said:"My nation will pass through five stages. For forty years (they will be) people of righteousness and piety. Then those who follow them, for the next one hundred and twenty years, will be people who show mercy to one another and uphold ties with one another. Then those who follow them for the next one hundred and sixty years will be people who will turn their backs on one another and sever ties with one another. Then there will be Harj after Harj (killing). Seek deliverance, seek deliverance."