Arfajah narrated: We were talking about the month of Ramadan, and Utbah bin Farqad (may Allah be pleased with him) asked: What are you talking about? We said: About the month of Ramadan. He said: I heard the Messenger of Allah (peace and blessings be upon him) saying: "In it the gates of Paradise are opened and the gates of Hell are closed, in it the devils are chained, and in it a caller calls out every night: O seeker of good, come forward; and O seeker of evil, desist."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14397