Sahih Muslim 1014 a
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
If anyone gives as Sadaqa the equivalent of a date from that (earning) earned honestly, for Allah accepts that which is lawful, the Lord would accept it with His Right Hand, and even if it is a date, it would foster in the Hand of the lord, as one of you fosters his colt, till it becomes bigger than a mountain.
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ، عَنْ سَعِيدِ بْنِ يَسَارٍ، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ مَا تَصَدَّقَ أَحَدٌ بِصَدَقَةٍ مِنْ طَيِّبٍ - وَلاَ يَقْبَلُ اللَّهُ إِلاَّ الطَّيِّبَ - إِلاَّ أَخَذَهَا الرَّحْمَنُ بِيَمِينِهِ وَإِنْ كَانَتْ تَمْرَةً فَتَرْبُو فِي كَفِّ الرَّحْمَنِ حَتَّى تَكُونَ أَعْظَمَ مِنَ الْجَبَلِ كَمَا يُرَبِّي أَحَدُكُمْ فَلُوَّهُ أَوْ فَصِيلَهُ ‏"‏ ‏.‏