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 ‏"‏‏.‏