Sahih al-Bukhari, Book 80, Hadith 56 (In-Book) ⓘ
Narrated Ibn Abi `Aufa: Whenever somebody brought alms to the Prophet the used to say, "Allahumma Salli 'Alaihi (O Allah! Send Your Salat (Grace and Honor) on him)." Once when my father brought his alms to him, he said, "O Allah! Send Your Salat (Grace and Honor) on the family of Abi `Aufa."
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرِو بْنِ مُرَّةَ، عَنِ ابْنِ أَبِي أَوْفَى، قَالَ كَانَ إِذَا أَتَى رَجُلٌ النَّبِيَّ صلى الله عليه وسلم بِصَدَقَتِهِ قَالَ " اللَّهُمَّ صَلِّ عَلَيْهِ" فَأَتَاهُ أَبِي بِصَدَقَتِهِ فَقَالَ " اللَّهُمَّ صَلِّ عَلَى آلِ أَبِي أَوْفَى"
also referenced under: Hadith 6359 (DarusSalam) & Volume 8, Book 75, Hadith 370 (USC-MSA)