أَنَّ أَبَا بَكْرٍ كَانَ يُصَلِّي لَهُمْ فِي وَجَعِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الَّذِي تُوُفِّيَ فِيهِ حَتَّى إِذَا كَانَ يَوْمُ الِاثْنَيْنِ وَهُمْ صُفُوفٌ فِي الصَّلَاةِ ، فَكَشَفَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سِتْرَ الْحُجْرَةِ يَنْظُرُ إِلَيْنَا وَهُوَ قَائِمٌ كَأَنَّ وَجْهَهُ وَرَقَةُ مُصْحَفٍ
Abu Bakr عليه السلام used to lead the people in prayer during the fatal illness of the Rasool صلی اللہ علیہ وسلم ill it was Monday. When the people aligned (in rows) for the prayer the Rasool صلی اللہ علیہ وسلم lifted the curtain of his house and started looking at us and was standing at that time. His face was (glittering) like a page of the Qur'an and he smiled cheerfully.
[Sahih Bukhari 680, Sahih Muslim 419]
-Taken from Wafat un Nabi صلی اللہ علیہ وسلم by Imam An Nasai رحمہ اللہ