13ذٰلِكَ بِأَنَّهُم شاقُّوا اللَّهَ وَرَسولَهُ ۚ وَمَن يُشاقِقِ اللَّهَ وَرَسولَهُ فَإِنَّ اللَّهَ شَديدُ العِقابِBijan MoeinianThis was in account of their challenging God and His prophet. Whoever opposes God and His Prophet should know that God is severing in punishment.