كتاب الزكاة
12  
The Book of Zakat
(54)
Chapter: The supplication for the one who brings Charity
(54)
باب الدُّعَاءِ لِمَنْ أَتَى بِصَدَقَتِهِ ‏‏
Sahih Muslim 1078 b

This hadith has been narrated by Shu'ba with the same chain of transmitters (but with a slight variation of words, that he said):

(O Allah), bless them."
وَحَدَّثَنَاهُ ابْنُ نُمَيْرٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ إِدْرِيسَ، عَنْ شُعْبَةَ، بِهَذَا الإِسْنَادِ غَيْرَ أَنَّهُ قَالَ ‏ "‏ صَلِّ عَلَيْهِمْ ‏"‏ ‏.‏
Reference : Sahih Muslim 1078b
In-book reference : Book 12, Hadith 230
USC-MSA web (English) reference : Book 5, Hadith 2359
  (deprecated numbering scheme)