Jami` at-Tirmidhi, Hadith 3359 ⓘ
Anas narrated [regarding Allah, Most High’s saying] ‘Verily We have granted you Al-Kauthar’ (108: 1) that the Prophet said: “It is a river in Paradise.” He said: “The Prophet said: ‘I saw a river in Paradise, whose banks had tents were made of pearl. I said: “What is this O Jibril?’” He said: “This is Al-Kauthar which Allah has granted you.”
حَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنْ مَعْمَرٍ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ : ( إناَّ، أَعْطَيْنَاكَ الْكَوْثَرَ ) أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " هُوَ نَهْرٌ فِي الْجَنَّةِ " . قَالَ فَقَالَ النَّبِيُّ صلى الله عليه وسلم " رَأَيْتُ نَهْرًا فِي الْجَنَّةِ حَافَتَاهُ قِبَابُ اللُّؤْلُؤِ قُلْتُ مَا هَذَا يَا جِبْرِيلُ قَالَ هَذَا الْكَوْثَرُ الَّذِي قَدْ أَعْطَاكَهُ اللَّهُ " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
also referenced under: Book 47, Hadith 3684 (In-Book) & Volume 6, Book 44, Hadith 3359 (DarusSalam)