The reward of building a mosque for Allah’s Sake

عُبَيْدَ اللَّهِ الْخَوْلاَنِيَّ، أَنَّهُ سَمِعَ عُثْمَانَ بْنَ عَفَّانَ، يَقُولُ عِنْدَ قَوْلِ النَّاسِ فِيهِ حِينَ بَنَى مَسْجِدَ الرَّسُولِ صلى الله عليه وسلم إِنَّكُمْ أَكْثَرْتُمْ، وَإِنِّي سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏ “‏ مَنْ بَنَى مَسْجِدًا ـ قَالَ بُكَيْرٌ حَسِبْتُ أَنَّهُ قَالَ ـ يَبْتَغِي بِهِ وَجْهَ اللَّهِ، بَنَى اللَّهُ لَهُ مِثْلَهُ فِي الْجَنَّةِ ‏”‏‏.‏

Hazrat ‘Ubaidullah al-Khawlani narrated: He heard Hazrat ‘Uthman ibn ‘Affan^ra say, when people were criticising him about rebuilding the Mosque of Allah’s Messenger^sa: “You have spoken at length, whereas I myself heard the Prophet^sa say, ‘Whoever builds a mosque – [Bukair (one of the narrators) said he believed the words were] intending Allah’s pleasure – Allah will build a similar [building] for him in Paradise.’”

(Sahih al-Bukhari, Kitab as-salah, Bab mun bana masjidan, Hadith 450)