Abu Saeed Khudri reported,
The Prophet ﷺ delivered a sermon and said, "Allah has given a servant the choice between this world and what is with Him, and he chose what is with Allah."Abu Bakr 
wept. I said to myself, "What makes this old man weep? If Allah has given a servant the choice between this world and what is with Him, and he chose what is with Allah, then the Messenger of Allah ﷺ is the servant." Abu Bakr was the most knowledgeable among us.The Prophet said, "Abu Bakr, do not weep. The most generous of people toward me in his companionship and his wealth is Abu Bakr. If I were to take a close friend from my community, I would have taken Abu Bakr, but the brotherhood and affection of Islam suffices. Let no door remain open in the mosque except the door of Abu Bakr."
Azami 9827
Sahihعن أبي سعيد الخدري قال
خطب النبي ﷺ، فقال: إن الله خير عبدا بين الدنيا وبين ما عنده فاختار ما عند الله، فبكى أبو بكر رضي الله عنه، فقلت في نفسي: ما يبكي هذا الشيخ؟ إن يكن الله خير عبدا بين الدنيا وبين ما عنده فاختار ما عند الله، فكان رسول الله ﷺ هو العبد، وكان أبو بكر أعلمنا، قال: يا أبا بكر، لا تبك، إن أمن الناس علي في صحبته وماله أبو بكر، ولو كنت متخذا خليلا من أمتي لاتخذت أبا بكر، ولكن أخوة الإسلام ومودته، لا يبقين في المسجد باب إلا سد إلا باب أبي بكر.
Bukhari narrated it in the Book of Prayer (466), and Muslim in the Book of the Virtues of the Companions (2382-2), both through the route of Abu Nadr, from Ubayd bin Hunayn, from Abu Saeed Khudri, who said, and then he mentioned it.Bukhari added in his narration, from Muhammad bin Sinan, Fulayh narrated to us, Abu Nadr narrated to us, from Ubayd bin Hunayn, "from Busr bin Saeed," from Abu Saeed Khudri. So he added Busr bin Saeed between Ibn Hunayn and Abu Saeed Khudri.Bukhari said, "This is how Muhammad bin Sinan narrated it, and it is a mistake. It is rather from Ubayd bin Hunayn, and from Busr bin Saeed," meaning with the conjunctive "and." According to this, Abu Nadr heard it from two teachers, each of whom narrated it to him from Abu Saeed.I say, Bukhari narrated in the Book of the Virtues of the Companions (3654) through another route from Abu Nadr, from Busr bin Saeed, and in the Book of the Virtues of the Ansar (3904) through another route from Abu Nadr, from Ubayd bin Hunayn, both from Abu Saeed Khudri with similar wording.