سنن النسائي

Abdullah bin As-Sa'di narrated that he came to 'Umar bin Al-Khattab during his Caliphate and 'Umar said to him: "I heard that you do some jobs for the people but when payment is given to you, you refuse it." I said: "(that is so)." 'Umar, may Allah be pleased with him, said: "Why do you do that? I said: "I have horses and slaves and am well off, and I wanted my work to be an act of charity toward the Muslims." 'Umar said to him: "Do not do that. I used to want the same thing as you. The Messenger of Allah (ﷺ) used to give me payment and I would say, 'Give it to someone who is more in need of it that I am.' But the Messenger of Allah (ﷺ) said: "Take it and keep it or give it in charity. Whatever comes to you of this wealth when you are not hoping for it and not asking for it, take it, and whatever does not, then do not wish for it. "'