Musnad Abu Ya'la al-Mawsili 150:352

Al-Hasan ibn Hammad narrated to us, 'Abdah ibn Sulayman narrated to us, Yahya ibn Sa'id narrated to us, from 'Abdullah ibn 'Amir ibn Rabi'ah, from 'Aishah, who said: The Messenger of Allah (may Allah bless him and grant him peace) was restless one night, then he said: "I wish a righteous man from my companions would come to guard me tonight." She said: Then we heard the sound of weapons. He said: "Who is this?" He said: "I am Sa'd ibn Abi Waqqas; I have come to guard you." She said: So he slept until I heard his snoring.