The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness (Kitab Al-Dhikr)
Muslim :: Book 35 : Hadith 6547
This hadith has been transmitted on the authority of al-Bara' b. 'Azib that Allah's Messenger (may peace be upon him) said to a person: O, so and so, as you go to your bed; the rest of the hadith is the same but with this variation of wording that he said:" Thine Apostle whom Thou sent." If you die that night you would die on Fitra and if you get up in the morning you would get up with a bliss.