Prayer (Kitab Al-Salat)
Dawud :: Book 2 : Hadith 447
Narrated Abdullah ibn Mas'ud:
We proceeded with the Apostle of Allah (peace_be_upon_him) on the occasion of al-Hudaybiyyah. The Apostle of Allah (peace_be_upon_him) said: Who will keep watch for us? Bilal said: I (shall do). The overslept till the sun arose. The Prophet (peace_be_upon_him) awoke and said: Do as you used to do (i.e. offer prayer as usual). Then we did accordingly. He said: Anyone who oversleeps or forgets (prayer) should do similarly.