Riyad as-Salihin 1723
Ibn 'Umar (May Allah be pleased with them) said:
The Messenger of Allah (ﷺ) said, "Grant shelter to him who begs for it in the Name of Allah, give to him who begs in the Name of Allah, accept the invitation of him who invites you, and requite him who does a favour to you, but if you are unable to requite him, go on praying for him till you are sure that you have requited him adequately." [Abu Dawud and An- Nasa'i] .
وعن ابن عمر رضي الله عنهما قال‏:‏ قال رسول الله صلى الله عليه وسلم ‏:‏ ‏
"‏من استعاذ بالله فأعيذوه، ومن سأل بالله، فأعطوه، ومن دعاكم فأجيبوه، ومن صنع إليكم معروفًا فكافئوه، فإن لم تجدوا ما تكافئونه به، فادعوا له حتى تروا أنكم قد كافأتموه‏"‏‏.‏ ‏(‏‏(‏حديث صحيح رواه أبو داود والنسائي بأسانيد الصحيحين‏)‏‏)‏