Sunan Ibn Majah 736
سنن ابن ماجه#736Sahihحَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا أَبُو بَكْرٍ الْحَنَفِيُّ، حَدَّثَنَا عَبْدُ الْحَمِيدِ بْنُ جَعْفَرٍ، عَنْ أَبِيهِ، عَنْ مَحْمُودِ بْنِ لَبِيدٍ، عَنْ عُثْمَانَ بْنِ عَفَّانَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ " مَنْ بَنَى لِلَّهِ مَسْجِدًا بَنَى اللَّهُ لَهُ مِثْلَهُ فِي الْجَنَّةِ " .
It was narrated that 'Uthman bin 'Affan said:"I heard the Messenger of Allah say: 'Whoever builds a mosque for the sake of Allah, Allah will build something similar for him in Paradise
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 4:2