وَلَقَدْ جِئْنَاهُمْ بِكِتَابٍ فَصَّلْنَاهُ عَلَىٰ عِلْمٍ هُدًى وَرَحْمَةً لِقَوْمٍ يُؤْمِنُونَ

Certainly, We have brought to them a Book (the Quran) which We have explained in detail with knowledge, - a guidance and a mercy to a people who believe.