Allah is the Light of the heavens and the earth. The parable of His Light is as if there were a niche and within it a lamp: The Lamp enclosed in Glass; the glass as it were a brilliant star: Lit from a blessed Tree, an Olive, neither of the East nor of the West, whose Oil is well-nigh luminous, though fire scarce touched it: Light upon Light! Allah doth guide whom He will to His light: Allah doth set forth Parables for men: and Allah doth know all things.[Qur'an 24:35]
Narrated Al-Aswad(RA): I asked 'Aisha(RA) "How is the night prayer of the Prophet(PBUH)?" She replied, "He used to sleep early at night, and get up in its last part to pray, and then return to his bed. When the Muadh-dhin pronounced the Adhan, he would get up. If he was in need of a bath he would take it; otherwise he would perform ablution and then go out (for the prayer)."