Sahih Muslim Book 20, Hadith Number 4510.

Chapter : Acceptance of gifts on the part of state officers is forbidden.

It has been reported on the authority of Abu Humaid as-Sa’idi who said: The Holy Prophet (may peace be upon him) appointed Ibn Lutbiyya, a man from the Azd tribe, in charge of Sadaqa (authorising him to receive gifts from the people on behalf of the State). He came with the collection, gave it to the Holy Prophet (may peace be upon him), and said: This wealth is for you and this is a gift presented to me. The Holy Prophet (may peace be upon him) said to him: Why didn’t you remain in the house of your father and your mother to see whether gifts were presented to you or not. Then he stood up to deliver a sermon. Here follows the tradition like the tradition of Sufyan.