What he was given while they thought he slept
He raised his head smiling, and they asked what had made him smile.
نَهْرٌ وَعَدَنِيهِ رَبِّي عَزَّ وَجَلَّ فِي الْجَنَّةِ عَلَيْهِ حَوْضٌ
A sūrah was revealed to me just now, and he recited: In the name of Allah, the Most Merciful, the Most Compassionate. Indeed We have given you al-Kawthar. Then he asked: do you know what al-Kawthar is? It is a river my Lord has promised me in Paradise, over which is a basin.
The full narration
Mukhtar b. Fulful reported that he had heard Anas b. Malik say that the Messenger of Allah (ﷺ) dozed off, and the rest of the hadith is the same as transmitted by Mus-hir except for the words that he (the Holy Prophet) said:It (Kauthar) is a canal which my Lord the Exalted and the Glorious has promised me in Paradise. There is a tank over it, but he made no mention of the tumblers like the number of the stars
Source
Ṣaḥīḥ Muslim · 895
- Agreed upon as authentic (al-Bukhārī / Muslim)