Word by Word Analysis

إِنَّ ٱلَّذِينَ فَرَّقُوا۟ دِينَهُمْ وَكَانُوا۟ شِيَعًا لَّسْتَ مِنْهُمْ فِى شَىْءٍ ۚ إِنَّمَآ أَمْرُهُمْ إِلَى ٱللَّهِ ثُمَّ يُنَبِّئُهُم بِمَا كَانُوا۟ يَفْعَلُونَ 159

Indeed, those who have divided their religion and become sects - you, [O Muḥammad], are not [associated] with them in anything. Their affair is only [left] to Allāh; then He will inform them about what they used to do.