Sunan Ibn Majah, Chapter: The Chapters on Tribulations

from his father, that his grandfather said: from his father, that his grandfather said:"The Messenger of Allah (saw) said: 'The Hour will not begin until the closest Muslim outpost will be at Baula'.' Then he said: 'O Ali, O Ali, O Ali.' He (Ali) said: 'May my father and mother be ransomed for you.' He said: 'You will fight Banu Asfar (the Romans) and those who come after you will fight them, until the best of the Muslims go out to fight them, the people of Hijaz who do not fear the blame of anyone for the sake of Allah. They will conquer Constantinople with Tasbih and Takbir and will acquire such spoils of war as has never been seen before, which they will distribute by the shieldful. Someone will come and say: "Masih has appeared in your land!" But he will be lying, so the one who takes (some of the spoils) will regret it, and the one who leaves it behind will regret it too.'"