﴿ مِن قَبْلُ هُدًۭى لِّلنَّاسِ وَأَنزَلَ ٱلْفُرْقَانَ ۗ إِنَّ ٱلَّذِينَ كَفَرُوا۟ بِـَٔايَٰتِ ٱللَّهِ لَهُمْ عَذَابٌۭ شَدِيدٌۭ ۗ وَٱللَّهُ عَزِيزٌۭ ذُو ٱنتِقَامٍ ﴾

“aforetime, as a guidance unto mankind, and it is He who has bestowed [upon man] the standard by which to discern the true from the false. Behold, as for those who are bent on denying God's messages - grievous suffering awaits them: for God is almighty, an avenger of evil.”

(Aforetime) before Muhammad and the Qur'an, (for a guidance to mankind) as a guidance from error to the Children of Israel; (and hath revealed the Criterion (of right and wrong)) He revealed the Qur'an to Muhammad in instalments to differentiate the lawful from the unlawful. (Lo! those who disbelieve the revelations of Allah) Muhammad and the Qur'an, referring in this context to the delegation of Najran, (theirs will be a heavy doom) in this world and in the next. (Allah is Mighty) powerful in His vengeance, (Able to Requite (the wrong)) able to carry His vengeance out on them.