Sunan Ibn Majah 739
سنن ابن ماجه#739SahihIt was narrated that Anas bin Malik said:"The Messenger of Allah said: 'The Hour will not begin until the people compete in (building) mosques
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 4:5