Sahih Muslim Book 4, Hadith Number 1039.

Chapter : The excellence of the prayer and the way it is begun and the excellence of Ruku’ and moderation in it and prostration and moderation in it, etc.

Al-Aswad reported that ‘Aisha said: You have made us equal to the dogs and the asses, whereas I lay on the bedstead and the Messenger of Allah (may peace be upon him) came there and stood in the middle of the bedstead and said prayer. I did not like to take off the quilt from me (in that state), so I moved away quietly from the front legs of the bedstead and thus came out of the quilt.