Surat Al-Baqarah [2:245]

مَّن ذَا ٱلَّذِى يُقْرِضُ ٱللَّهَ قَرْضًا حَسَنًۭا فَيُضَـٰعِفَهُۥ لَهُۥٓ أَضْعَـٰفًۭا كَثِيرًۭا ۚ وَٱللَّهُ يَقْبِضُ وَيَبْصُطُ ۥ وَإِلَيْهِ تُرْجَعُونَ

Who will lend to Allah a good loan which Allah will multiply many times over? It is Allah ‘alone’ who decreases and increases ‘wealth’.
And to Him you will ‘all’ be returned.

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Sunan Ibn Majah, Kitab al-Masajid wal Jamaah, Hadith 738

عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ، أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ، مَنْ بَنَى مَسْجِدًا كَمَفْحَصِ قَطَاةٍ أَوْ أَصْغَرَ، بَنَى اللَّهُ لَهُ بَيْتًا فِي الْجَنَّةِ

Whoever builds a mosque for the sake of Allah, like a sparrow’s nest or even smaller, Allah will build for him a house in Paradise.