Allah, exalted be His praise, says: "In the name of Allah, the Most Gracious, the Most Merciful."
"Indeed, We sent it (the Qur'an) down on the Night of Decree. And what will make you know what the Night of Decree is? The Night of Decree is better than a thousand months. The angels and the Spirit (Jibril) descend therein by the permission of their Lord for every matter. Peace it is, until the rising of the dawn." [Surah al-Qadr: 1-5]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / Q8521