كتاب الزكاة
12  
The Book of Zakat
(11)
Chapter: Encouragement to spend and glad tidings of compensation for the one who spends on good deeds
(11)
باب الْحَثِّ عَلَى النَّفَقَةِ وَتَبْشِيرِ الْمُنْفِقِ بِالْخَلَفِ ‏‏
Sahih Muslim 993 b

Abu Huraira reported Allah's Messenger (ﷺ) as saying that Allah said to him:

" Spend, I will bestow upon you." And the Messenger of Allah (ﷺ) said: The right hand of Allah is full and spending (the riches) liberally during day and night will not diminish (the resources of Allah). Don't you see what (an enormous amount of resources) He has spent since He created the heaven and the earth, and what is in His right hand has not decreased? His Throne is upon the water. And in His other hand is death, and He elevates and degrades (whom He likes).
وَحَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ بْنُ هَمَّامٍ، حَدَّثَنَا مَعْمَرُ بْنُ رَاشِدٍ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، أَخِي وَهْبِ بْنِ مُنَبِّهٍ قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم فَذَكَرَ أَحَادِيثَ مِنْهَا ‏.‏ وَقَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّ اللَّهَ قَالَ لِي أَنْفِقْ أُنْفِقْ عَلَيْكَ ‏"‏ ‏.‏ وَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ يَمِينُ اللَّهِ مَلأَى لاَ يَغِيضُهَا سَحَّاءُ اللَّيْلَ وَالنَّهَارَ أَرَأَيْتُمْ مَا أَنْفَقَ مُذْ خَلَقَ السَّمَاءَ وَالأَرْضَ فَإِنَّهُ لَمْ يَغِضْ مَا فِي يَمِينِهِ ‏"‏ ‏.‏ قَالَ ‏"‏ وَعَرْشُهُ عَلَى الْمَاءِ وَبِيَدِهِ الأُخْرَى الْقَبْضُ يَرْفَعُ وَيَخْفِضُ ‏"‏ ‏.‏
Reference : Sahih Muslim 993b
In-book reference : Book 12, Hadith 46
USC-MSA web (English) reference : Book 5, Hadith 2179
  (deprecated numbering scheme)