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 ‏"‏ ‏.‏

Abu Huraira reported Allah's Messenger (PBUH) 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. Translation Not Available

Book Ref: Sahih Muslim Book 12 Hadith 2211
Web Ref:  Sahih Muslim Book 5 Hadith 1014 a