Sahih Muslim 2382 a
Abu Sa'id reported that Allah's Messenger (ﷺ) sat on the pulpit and said:
Allah gave a choice to His servant that he may opt the beauties of the world or that which is with Him and the servant chose that which was with Him. Thereupon Abu Bakr wept and he wept bitterly and said: Let our fathers and our mothers be taken as ransom for you. It was Allah's Messenger (ﷺ) who had been given the choice and Abu Bakr knew it better than us, and Allah's Messenger (ﷺ) is reported to have said: Behold, of all people the most generous toward me in regard to his companionship and his property was Abu Bakr and were I to choose anyone as my bosom friend, I would have chosen Abu Bakr as my dear friend, but (for him) I cherish Islamic brotherliness and love. There shall be left open no window in the mosque except Abu Bakr's window.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ جَعْفَرِ بْنِ يَحْيَى بْنِ خَالِدٍ، حَدَّثَنَا مَعْنٌ، حَدَّثَنَا مَالِكٌ، عَنْ أَبِي،
 النَّضْرِ عَنْ عُبَيْدِ بْنِ حُنَيْنٍ، عَنْ أَبِي سَعِيدٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم جَلَسَ عَلَى
 الْمِنْبَرِ فَقَالَ ‏"‏ عَبْدٌ خَيَّرَهُ اللَّهُ بَيْنَ أَنْ يُؤْتِيَهُ زَهْرَةَ الدُّنْيَا وَبَيْنَ مَا عِنْدَهُ فَاخْتَارَ مَا عِنْدَهُ
 ‏"‏ ‏.‏ فَبَكَى أَبُو بَكْرٍ وَبَكَى فَقَالَ فَدَيْنَاكَ بِآبَائِنَا وَأُمَّهَاتِنَا ‏.‏ قَالَ فَكَانَ رَسُولُ اللَّهِ صلى
 الله عليه وسلم هُوَ الْمُخَيَّرُ وَكَانَ أَبُو بَكْرٍ أَعْلَمَنَا بِهِ ‏.‏ وَقَالَ رَسُولُ اللَّهِ صلى الله عليه
 وسلم ‏"‏ إِنَّ أَمَنَّ النَّاسِ عَلَىَّ فِي مَالِهِ وَصُحْبَتِهِ أَبُو بَكْرٍ وَلَوْ كُنْتُ مُتَّخِذًا خَلِيلاً لاَتَّخَذْتُ
 أَبَا بَكْرٍ خَلِيلاً وَلَكِنْ أُخُوَّةُ الإِسْلاَمِ لاَ تُبْقَيَنَّ فِي الْمَسْجِدِ خَوْخَةٌ إِلاَّ خَوْخَةَ أَبِي بَكْرٍ ‏"‏ ‏.‏