"What is Al-Kawthar?" He said: "That is a river that Allah has given me"- that is, in Paradise- 'whiter than milk and sweeter than honey. In it are birds whose necks are like the necks of camels." 'Umar said: "Indeed this is plump and luxurious then." So the Messenger of Allah ﷺ said, "Those who consume it are more plumb than it." (Using translation from Tirmidhī 2542)
أَنَّ رَجُلًا جَاءَ إِلَى رَسُولِ اللهِ ﷺ فَقَالَ يَا رَسُولَ اللهِ مَا الْكَوْثَرُ؟ قَالَ «نَهْرٌ أَعْطَانِيهِ رَبِّي فِي الْجَنَّةِ هُوَ أَشَدُّ بَيَاضًا مِنَ اللَّبَنِ وَأَحْلَى مِنَ الْعَسَلِ فِيهِ طُيُورٌ أَعْنَاقُهَا كَأَعْنَاقِ الْجُزُرِ» قَالَ عُمَرُ ؓ يَا رَسُولَ اللهِ إِنَّهَا لَنَاعِمَةٌ قَالَ «آكِلُهَا أَنْعَمُ مِنْهَا»