"On the Day of Resurrection a group of companions will come to me, but will be driven away from the Lake-Fount, and I will say, 'O Lord (those are) my companions!' It will be said, 'You have no knowledge as to what they innovated after you left; they turned apostate as renegades (reverted from Islam).
Sahih al-Bukhari Book 81, Hadith 173
← Previous Hadith An-Nu`man bin Abi `Aiyash, on hearing me, said. "Did you hear this from Sahl?" I said, "Yes." He said, " I bear witness that I heard Abu Sa`id Al-Khudri saying the same, adding that the Prophet (ﷺ) said: 'I will say: They are of me (i.e. my followers). It will be said, 'You do not know what they innovated (new things) in the religion after you left'. I will say, 'Far removed, far removed (from mercy), those who changed (their religion) after me."

Sahih al-Bukhari Book 81, Hadith 172 Next Hadith → The companions of the Prophet (ﷺ) said, "Some men from my companions will come to my Lake-Fount and they will be driven away from it, and I will say, 'O Lord, my companions!' It will be said, 'You have no knowledge of what they innovated after you left: they turned apostate as renegades (reverted from Islam).

Sahih al-Bukhari Book 81, Hadith 174