حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا هُشَيْمٌ، حَدَّثَنَا أَبُو بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ أَنَّهُ قَالَ فِي الْكَوْثَرِ هُوَ الْخَيْرُ الَّذِي أَعْطَاهُ اللَّهُ إِيَّاهُ‏.‏ قَالَ أَبُو بِشْرٍ قُلْتُ لِسَعِيدِ بْنِ جُبَيْرٍ فَإِنَّ النَّاسَ يَزْعُمُونَ أَنَّهُ نَهَرٌ فِي الْجَنَّةِ‏.‏ فَقَالَ سَعِيدٌ النَّهَرُ الَّذِي فِي الْجَنَّةِ مِنَ الْخَيْرِ الَّذِي أَعْطَاهُ اللَّهُ إِيَّاهُ‏.‏

Narrated Abu Bishr: 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." Translation Not Available

Book Ref: Sahih Bukhari Book 65 Hadith 4966
Web Ref:  Sahih Bukhari Vol 6 Book 60 Hadith 490