Sunan Ibn Majah
2779
Daif+3

It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:“Even if there was only one day left of this world, Allah would make it last until a man from my household took possession of (the mountain of) Dailam and Constantinople.”

DaifAl-Albani
DaifMuhammad Fouad Abd al-Baqi