Sahih al-Bukhari, Hadith 6028 ⓘ
Narrated Abu Musa: Whenever a beggar or a person in need came to the Prophet, the Prophet would say "Help and recommend him and you will receive the reward for it, and Allah will bring about what he will through His Prophet's tongue
حَدَّثَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ بُرَيْدٍ، عَنْ أَبِي بُرْدَةَ، عَنْ أَبِي مُوسَى، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ كَانَ إِذَا أَتَاهُ السَّائِلُ أَوْ صَاحِبُ الْحَاجَةِ قَالَ " اشْفَعُوا فَلْتُؤْجَرُوا، وَلْيَقْضِ اللَّهُ عَلَى لِسَانِ رَسُولِهِ مَا شَاءَ " .
also referenced under: Book 78, Hadith 58 (In-Book) & Volume 8, Book 73, Hadith 56 (USC-MSA)