Compiled by Imam Muhammad al-Bukhari
حَدَّثَنَا آدَمُ، حَدَّثَنَا شَيْبَانُ، حَدَّثَنَا قَتَادَةُ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ لَمَّا عُرِجَ بِالنَّبِيِّ صلى الله عليه وسلم إِلَى السَّمَاءِ قَالَ " أَتَيْتُ عَلَى نَهَرٍ حَافَتَاهُ قِبَابُ اللُّؤْلُؤِ مُجَوَّفًا فَقُلْتُ مَا هَذَا يَا جِبْرِيلُ قَالَ هَذَا الْكَوْثَرُ ".
When the Prophet (ﷺ) was made to ascend to the Heavens, he said (after his return), "I came upon a river the banks of which were made of tents of hollow pearls. I asked Gabriel. What is this (river?) He replied, 'This is the Kauthar.'