﴿ وَلَقَدْ جِئْنَٰهُم بِكِتَٰبٍۢ فَصَّلْنَٰهُ عَلَىٰ عِلْمٍ هُدًۭى وَرَحْمَةًۭ لِّقَوْمٍۢ يُؤْمِنُونَ ﴾

“for, indeed, We did convey unto them a divine writ which We clearly, and wisely, spelled out - a guidance and a grace unto people who will believe."”

And indeed We have brought them that is the people of Mecca a Book the Qur’ān which We have detailed which We have made clear through tidings and the Promise of reward and the Threat of punishment with knowledge ‘alā ‘ilmin is a circumstantial qualifier in other words ‘knowing what has been detailed in it’ a guidance hudan is also a circumstantial qualifier referring to the hā’ the suffixed pronoun of fassālnā-hu ‘which We have detailed’ and a mercy for a people who believe in it.