Chapter 2, Verse 185, of the Quran states:
The month of Ramadan is that in which was revealed the Quran; a guidance for humans, and clear proofs of the guidance, and the criterion (of right and wrong). And whosoever of you is present, let him fast the month, and whosoever of you is sick or on a journey, a number of other days. Allah desires for you ease; He desires not hardship for you; and that you should complete the period, and that you should magnify Allah for having guided you, and that perhaps you may be thankful.[Quran 2:185]
It is believed that the Quran was first revealed to Muhammad during the month of Ramadan which has been referred to as the "best of times". The first revelation was sent down on Laylat al-Qadr (The night of Power) which is one of the five odd nights of the last ten days of Ramadan.[According to hadith, all holy scriptures were sent down during Ramadan. It is further believed that the tablets of Ibrahim, the Torah, the Psalms, the Gospel and the Quran were sent down on 1st, 6th, 12th, 13th and 24th Ramadan, respectively.