Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When the first night of Ramadan comes, the rebellious devils are chained up, and the gates of Hell are closed and not a single one of them is opened, while the gates of the Gardens are opened and not a single one of them is closed. And a caller calls out: O seeker of good, come forward! And O seeker of evil, cut short (stop)! And Allah Almighty also frees (people) from Hell."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8501