Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 1257
Narated By 'Aisha : When the Apostle of Allah (pbuh) finished his prayer late in the night, he would see. If I was awake, he would talk to me. If I was sleeping, he would awaken me, and pray two rak'ahs, then he would lie down as long as the muadhdhdin came to him and called him for the dawn prayer. Then he would pray two rak'ahs lightly and come out for the prayer.