Language:
كتاب الزكاة
24  
Obligatory Charity Tax (Zakat)
(21)
Chapter: To exhort one to give in charity
(21)
باب التَّحْرِيضِ عَلَى الصَّدَقَةِ وَالشَّفَاعَةِ فِيهَا
Sahih al-Bukhari 1432

Narrated Abu Burda bin Abu Musa:

that his father said, "Whenever a beggar came to Allah's Messenger (ﷺ) or he was asked for something, he used to say (to his companions), "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 مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، حَدَّثَنَا أَبُو بُرْدَةَ بْنُ عَبْدِ اللَّهِ بْنِ أَبِي بُرْدَةَ، حَدَّثَنَا أَبُو بُرْدَةَ بْنُ أَبِي مُوسَى، عَنْ أَبِيهِ ـ رضى الله عنه ـ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا جَاءَهُ السَّائِلُ، أَوْ طُلِبَتْ إِلَيْهِ حَاجَةٌ قَالَ ‏ "‏ اشْفَعُوا تُؤْجَرُوا، وَيَقْضِي اللَّهُ عَلَى لِسَانِ نَبِيِّهِ صلى الله عليه وسلم مَا شَاءَ ‏"‏‏.‏
Reference : Sahih al-Bukhari 1432
In-book reference : Book 24, Hadith 35
USC-MSA web (English) reference : Vol. 2, Book 24, Hadith 512
  (deprecated numbering scheme)