بُلُوغُ الْمَرَامِ
Bulugh al-Maram 610
The Book of Zakah
وَعَنْ عَبْدِ اَللَّهِ بْنِ أَبِي أَوْفَى - رضى الله عنه - قَالَ: { كَانَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -إِذَا أَتَاهُ قَوْمٌ بِصَدَقَتِهِمْ قَالَ: اَللَّهُمَّ صَلِّ عَلَيْهِمْ } مُتَّفَقٌ عَلَيْهِ [1] .
Abdullah bin Abi Aufa (RAA) narrated, ‘Whenever a person came to the Messenger of Allah (ﷺ) with their Zakah, he would say, “O Allah! Send your blessings upon them” Agreed upon.
Sunnah.com reference: Book 4, Hadith 13