Sayyidina Anas reported about (surah al-Kawthar) that the Prophet said, “It is a river in Paradise.” He then added, “I saw a river in Paradise on whose beds on either side are tents of pearl. I asked, ‘0 Jibril, what are they?’ He said, ‘It is al-Kawthar that Allah has granted you’.”
[Ahmed 12675,Bukhari 4964, Abu Dawud 4748]