Musnad Ahmad 133:1

Mu'awiyah ibn 'Amr and Abu Sa'id narrated to us, they said: Za'idah narrated to us, he said: Al-Sa'ib ibn Hubaysh al-Kala'i narrated to us, from Abu al-Shammakh al-Azdi, from a cousin of his who was among the companions of the Prophet, may God bless him and grant him peace, that he came to Mu'awiyah and entered upon him, and said: I heard the Messenger of God, may God bless him and grant him peace, say: "Whoever is entrusted with a matter of the people's affairs, then closes his door against the needy, the oppressed, or the one in need, God, Blessed and Exalted is He, will close the doors of His mercy against him at the time of his need and his poverty, when he is most in need of it."