Sahih al-Bukhari 81:172
Abu Hazim added:
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."
Reference
Sahih al-Bukhari 81:172
In-book reference
Book 81, Hadith 172
Arabic Text
قَالَ أَبُو حَازِمٍ فَسَمِعَنِي النُّعْمَانُ بْنُ أَبِي عَيَّاشٍ، فَقَالَ هَكَذَا سَمِعْتَ مِنْ، سَهْلٍ فَقُلْتُ نَعَمْ. فَقَالَ أَشْهَدُ عَلَى أَبِي سَعِيدٍ الْخُدْرِيِّ لَسَمِعْتُهُ وَهْوَ يَزِيدُ فِيهَا " فَأَقُولُ إِنَّهُمْ مِنِّي. فَيُقَالُ إِنَّكَ لاَ تَدْرِي مَا أَحْدَثُوا بَعْدَكَ. فَأَقُولُ سُحْقًا سُحْقًا لِمَنْ غَيَّرَ بَعْدِي ". وَقَالَ ابْنُ عَبَّاسٍ سُحْقًا بُعْدًا، يُقَالُ سَحِيقٌ بَعِيدٌ، وَأَسْحَقَهُ أَبْعَدَهُ.