﴿ وَلَا تَكُونُوا۟ كَٱلَّذِينَ تَفَرَّقُوا۟ وَٱخْتَلَفُوا۟ مِنۢ بَعْدِ مَا جَآءَهُمُ ٱلْبَيِّنَٰتُ ۚ وَأُو۟لَٰٓئِكَ لَهُمْ عَذَابٌ عَظِيمٌۭ ﴾

“And be not like those who have drawn apart from one another and have taken to conflicting views after all evidence of the truth has come unto them: for these it is for whom tremendous suffering is in store”

(And be ye not) divided in religion (as those who separated and disputed) in religion, such as the religious schisms that took place among the Jews and Christians (after the clear proofs) proofs from their Scriptures of Islam (had come unto them. For such) i.e. the Jews and Christians (there is an awful doom) greater than anything one can imagine.