The Book of Prayer - Travellers
6/17. Chapter:
Night prayers and the number of rak`ah offered by the Prophet (saws) at night, and that Witr is one rak`ah, and a one-rak`ah prayer is correct
Sahih Muslim
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَنَصْرُ بْنُ عَلِيٍّ، وَابْنُ أَبِي عُمَرَ، قَالَ أَبُو بَكْرٍ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَبِي النَّضْرِ، عَنْ أَبِي سَلَمَةَ، عَنْ عَائِشَةَ، قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم إِذَا صَلَّى رَكْعَتَىِ الْفَجْرِ فَإِنْ كُنْتُ مُسْتَيْقِظَةً حَدَّثَنِي وَإِلاَّ اضْطَجَعَ .
'A'isha reported: When the Messenger of Allah (ﷺ) had prayed the two rak'ahs (Sunan) of the dawn prayer, he would talk to me if I was awake, otherwise he would lie down.
Reference : Sahih Muslim 743aIn-book reference : Book 6, Hadith 161USC-MSA web (English) reference : Book 4, Hadith 1616