The Prophet (ﷺ) said, "There will be a tank (Lake-Fount) in front of you as large as the distance between Jarba and Adhruh (two towns in Sham).
Sahih al-Bukhari Book 81, Hadith 165
← Previous Hadith The Prophet (ﷺ) said, "I am your predecessor at the Lake-Fount, and some of you will be brought in front of me till I will see them and then they will be taken away from me and I will say, 'O Lord, my companions!' It will be said, 'You do not know what they did after you had left.'

Sahih al-Bukhari Book 81, Hadith 164 Next Hadith → The word 'Al-Kauthar' means the abundant good which Allah gave to him (the Prophet (ﷺ) Muhammad). Abu Bishr said: I said to Sa`id, "Some people claim that it (Al-Kauthar) is a river in Paradise." Sa`id replied, "The river which is in Paradise is one item of that good which Allah has bestowed upon him (Muhammad).

Sahih al-Bukhari Book 81, Hadith 166