Bukhari

Hadith Commentary:
(1)
Whoever apostatizes from the religion of Islam or introduces innovations (bid‘ah) into the religion of Islam will be kept away from the Hawd al-Kawthar on the Day of Resurrection.
Similarly, the person who suppresses the truth, commits injustice and oppression against people, and humiliates Islam and the people of Islam, will also face this punishment.
It is mentioned in the hadith that the Messenger of Allah (sallallahu alayhi wa sallam) said to Ka‘b ibn ‘Ujrah (radi Allahu anhu):
“I seek Allah’s protection for you from those rulers who will come after me.
Whoever goes to them, affirms their lies, and assists them in their oppression and injustice, he is not from me and I am not from him, and he will not be able to come near me at the Hawd al-Kawthar.
And whoever does not go to their doors, does not affirm their lies, and does not help them in their oppression and injustice, he is from me and I am from him.
He will come to me at the Hawd and will drink from its water.”
(Jami‘ al-Tirmidhi, Al-Fitan, Hadith: 2259)
(2)
We supplicate before Allah, the Exalted, that: O Allah! Grant us a good ending upon faith, and grant us the companionship of those who are successful and triumphant in Your presence, and on the Day of Resurrection grant us the ability to drink from the water of Hawd al-Kawthar at the hands of the Messenger of Allah (sallallahu alayhi wa sallam).
Amin, ya Rabb al-‘alamin.

Hadith Commentary: Benefits and Issues: It is evident from the supplication of Ibn Abi Mulaykah rahimahullah that he considered those people included as well who, after the era of Abu Bakr radi Allahu anhu, introduced new things into the religion or turned away from the religion. However, since they recited the kalimah of tawhid and accepted the religious rulings like Muslims—although they did not fully act upon them—they would still be perceived by him as members of the Ummah. That is why in some narrations the word "ashabi" (my companions) appears, and in others "min ummati" (from my Ummah), because there would be both types of people: that is, some who became apostates during the era of Abu Bakr, and some from the later Ummah who became perpetrators of innovations, as is established from the wording "min ummati."