Sa`id bin Jubair said that Ibn `Abbas said about Al-Kauthar. "That is the good which Allah has bestowed upon His Apostle." I said to Sa`id bin Jubair. "But the people claim that it is a river in Paradise." Sa`id said, "The river in Paradise is part of the good which Allah has bestowed on His Apostle."
Sahih al-Bukhari Book 65, Hadith 488
← Previous Hadith I asked `Aisha 'regarding the verse:--'Verily we have granted you the Kauthar.' She replied, "The Kauthar is a river which has been given to your Prophet on the banks of which there are (tents of) hollow pearls and its utensils are as numberless as the stars."

Sahih al-Bukhari Book 65, Hadith 487 Next Hadith → "When the "Surat-An-Nasr", 'When comes the Help of Allah and the conquest,' had been revealed to the Prophet (ﷺ) he did not offer any prayer except that he said therein, "Subhanka Rabbana wa bihamdika; Allahumma ighfirli (I testify the Uniqueness of our Lord, and all the praises are for Him: O Allah, forgive me!")

Sahih al-Bukhari Book 65, Hadith 489