Abu Dawud Book 2, Hadith Number 1348.

Chapter : On the number of rakahs of the prayer at night.

Narated By Abd Allah b. Abbas : I slept with the Prophet (PBUH). He saw that he (the Prophet) awoke, used tooth-stick, performed ablution, and recited: “In the creation of heavens and earth” to the end of the surah (‘Al ‘Imran. 190). He then stood up and prayed two rak’ahs in which he prolonged the standing, bowing, prostration; he then turned away and slept till he began to snore. This he did three times. this made six rak’ahs in all. He would use tooth-stick, then perform ablution, and recite those verses. He then observed the witr prayer. The version of ‘Uthman has: with three rak’ahs. The mu’adhdhdin then came to him and he went out for prayer. The version of Ibn ‘Isa adds: He then observed witr prayer; the Bilal came to him and called him for prayer when the dawn broke. He the prayed the two rak’ahs of the dawn prayer. He then went out for the prayer. Then both narrations were agreed: He began to supplicate saying: O Allah, place light in my heart, light in my tongue, light in my hearing, light in my eyesight, light on my right hand, light on my left hand, light in front of me, light behind me, light below me; O Allah, give me abundant light.