Language:
كتاب أخبار الآحاد
95  
Accepting Information Given by a Truthful Person
(3)
Chapter: Enter not the Prophet ’s (saws) houses unless permission is given to you…”
(3)
Sahih al-Bukhari 7262

Narrated Abu Musa:

The Prophet (ﷺ) entered a garden and told me to guard its gate. Then a man came and asked permission to enter. The Prophet, said, "Permit him and give him the good news that he will enter Paradise." Behold! It was Abu Bakr. Then `Umar came, and the Prophet (ﷺ) said, "Admit him and give him the good news that he will enter Paradise." Then `Uthman came and the Prophet (ﷺ) said, "Admit him and give him the good news that he will enter Paradise. "

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، عَنْ أَبِي عُثْمَانَ، عَنْ أَبِي مُوسَى، أَنَّ النَّبِيَّ صلى الله عليه وسلم دَخَلَ حَائِطًا وَأَمَرَنِي بِحِفْظِ الْبَابِ فَجَاءَ رَجُلٌ يَسْتَأْذِنُ فَقَالَ ‏"‏ ائْذَنْ لَهُ، وَبَشِّرْهُ بِالْجَنَّةِ ‏"‏‏.‏ فَإِذَا أَبُو بَكْرٍ، ثُمَّ جَاءَ عُمَرُ فَقَالَ ‏"‏ ائْذَنْ لَهُ، وَبَشِّرْهُ بِالْجَنَّةِ ‏"‏‏.‏ ثُمَّ جَاءَ عُثْمَانُ فَقَالَ ‏"‏ ائْذَنْ لَهُ، وَبَشِّرْهُ بِالْجَنَّةِ ‏"‏‏.‏
Reference : Sahih al-Bukhari 7262
In-book reference : Book 95, Hadith 16
USC-MSA web (English) reference : Vol. 9, Book 91, Hadith 367
  (deprecated numbering scheme)