He said regarding al-Kawthar, "It is the good which Allah has granted him."Abu Bishr said, I asked Saeed bin Jubayr, "But people claim it is a river in Paradise."Saeed replied, "The river in Paradise is part of the good which Allah has granted him."
قال في الكوثر: هو الخير الذي أعطاه الله إياه. قال أبو بشر: قلت لسعيد بن جبير: فإن الناس يزعمون أنه نهر في الجنة؟ فقال سعيد: النهر الذي في الجنة من الخير الذي أعطاه الله إياه.
Bukhari related it in the Tafsir (4966), from Yaqub bin Ibrahim, who said, Hushaym narrated to us, who said, Abu Bishr narrated to us, from Saeed bin Jubayr, from Ibn Abbas, and he mentioned it.His saying, "So pray to your Lord and sacrifice" [Kawthar 108:2], means give thanks to Allah who has granted you Kawthar. "Sacrifice" means the camels, so that you and your family may eat from them and distribute among the poor and needy, and what is meant by this is the sacrificial animals on the day of Eid al-Adha. Some jurists have deduced from this that what is meant here by "prayer" is the Eid prayer, and what is meant by "sacrifice" is the sacrificial offering, so the sacrifice comes after the prayer.As for His saying, "Indeed, the one who hates you is the one cut off" [Kawthar 108:3], al-abtar (the one cut off) refers to something partly severed. It came to be used predominantly for an animal whose tail has been cut off, then it was used for anyone who has sons and daughters, then the sons die while the daughters remain.His saying "the one who hates you" is an active participle from al-shanaah, which means hatred and enmity, meaning, indeed the one who hates you, O Muhammad, and hates what you have brought of guidance, truth, and proof, is the one who is cut off, disgraced, whose remembrance is severed.This was revealed concerning a group of the disbelievers of Makkah, when they said about the Prophet ﷺ, "Leave him, for he is a man cut off, he has no offspring, when he dies his remembrance will be severed." So Allah, exalted is He, responded to them with His saying, "Indeed, the one who hates you is the one cut off" [Kawthar 108:3]. And it has come to pass just as Allah, exalted is He, said, for the mention of Abu Lahab and Abu Jahl and the other chiefs of Quraysh has been cut off, while Allah preserved his remembrance ﷺ in the heavens, "Indeed, Allah and His angels send blessings upon the Prophet" [Ahzab 33:56], just as He preserved his remembrance on earth, "O you who believe, send blessings upon him and greetings of peace" [Ahzab 33:56], so his remembrance ﷺ has become manifest before all witnesses, no moment passes without his name being mentioned aloud throughout the inhabited world, "And I bear witness that Muhammad is the Messenger of Allah ﷺ." And Allah has made his sharia enduring until the Day of Gathering and the Return.