The holy month of Ramadan might have been prescribed, because it is a month in which the holy Prophet has perceived the truth. After this perception, the angels and the Qur'an have been sent down. By His power the angels are sent down and by the power of the grand wali, the Qur'an and angels are revealed. The grand Wali reached the truth of the Qur'an in the holy month and on the night of Qadr.