That is [deserved by them] because Allah has sent down the Book in truth. And indeed, those who differ over the Book are in extreme dissension.
The Saheeh International Quran Translation
ذَٰلِكَ بِأَنَّ ٱللَّهَ نَزَّلَ ٱلْكِتَٰبَ بِٱلْحَقِّ وَإِنَّ ٱلَّذِينَ ٱخْتَلَفُوا۟ فِى ٱلْكِتَٰبِ لَفِى شِقَاقٍۭ بَعِيدٍThat is [deserved by them] because Allah has sent down the Book in truth. And indeed, those who differ over the Book are in extreme dissension.