Mishkat al-Masabih — Hadith #39413

He said that once when he slept in the house of God’s Messenger, he awoke, cleaned his teeth and performed ablution, saying meanwhile, “In the creation of the heavens and the earth," to the end of the sura. He then stood up and prayed two rak'as, standing, bowing and prostrating himself at length in them. Then he finished, went to sleep and snored. He did that three times, six rak'as altogether, each time cleaning his teeth, performing ablution and reciting these verses. Then he performed a witr of three rak'as. Muslim transmitted it.