Al-Adab Al-Mufrad #880

'A'isha said, "The Prophet, may Allah bless him and grant him peace, was sleepless one night and said, 'Would that a man of righteous action among my Companions would come and guard me tonight!' Then he heard the sound of weapons. He asked, 'Who is it?' 'Sa'd,' came the answer. Sa'd said, 'Messenger of Allah, I have come to guard you.' The Messenger of Allah, may Allah bless him and grant him peace, slept and we heard him snore."