This hadith has been transmitted on the authority of al-Bara' b. 'Azib that Allah's Messenger (ﷺ) 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.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا أَبُو الأَحْوَصِ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ بْنِ، عَازِبٍ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لِرَجُلٍ " يَا فُلاَنُ إِذَا أَوَيْتَ إِلَى فِرَاشِكَ " . بِمِثْلِ حَدِيثِ عَمْرِو بْنِ مُرَّةَ غَيْرَ أَنَّهُ قَالَ " وَبِنَبِيِّكَ الَّذِي أَرْسَلْتَ . فَإِنْ مُتَّ مِنْ لَيْلَتِكَ مُتَّ عَلَى الْفِطْرَةِ وَإِنْ أَصْبَحْتَ أَصَبْتَ خَيْرًا " .
Muslim
The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness • Hadith 78