Sunan an-Nasa'i 2604

It was narrated that Ibn As-Sa'idi Al-Maliki said:"Umar bin Al-Khattab, may Allah be pleased with him, appointed me in charge of the Sadaqah. When I finished collecting it and handed it over to him, he ordered that I be given some payment. I said to him: 'I only did for the sake of Allah, the Mighty and Sublime, and my reward will be with Allah, the Mighty and Sublime.' He said: 'Take what I have given you: I did the same take during the time of the Messenger of Allah, and I said what you have said, but the Messenger of Allah said to me: "If you are given something without asking for it, then keep (some) and give (some) in charity