It is narrated from Hasan al-Basri (may Allah have mercy on him) that Sayyiduna Abdullah bin Amir appointed Kilab bin Umayyah as governor over al-Ubullah. Sayyiduna Uthman bin Abi al-As (may Allah be pleased with him) passed by him and asked him: "What is the matter with you?" He said: "I have been appointed governor over al-Ubullah." He said: "Shall I not tell you something?" He said: "Certainly." He said: I heard the Messenger of Allah (peace and blessings be upon him) say: "In the night there is an hour in which the gates of heaven are opened, and (Allah) says: Is there anyone asking, that I may give him? Is there anyone calling, that I may answer him? Is there anyone seeking forgiveness, that I may forgive him?" (The narrator) said: And that Dawud (peace be upon him) went out one night and said: Tonight no one will ask Allah for anything but that He will give it to him, except a sorcerer or a tithe-collector (an oppressive official). So he (the listener) boarded a small boat, came to Abdullah bin Amir and said: "Take back your post, for Uthman bin Abi al-As (may Allah be pleased with him) has told me such and such."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8343