﴿ إِنَّا نَحْنُ نَزَّلْنَا عَلَيْكَ ٱلْقُرْءَانَ تَنزِيلًۭا ﴾

“VERILY, [O believer,] it is We who have bestowed from on high this Qur’an upon thee, step by step - truly a bestowal from on high!”

Assuredly We nahnu reiterates the subject of innā ‘assuredly for the purpose of emphasis; alternatively it is a separating pronoun have revealed the Qur’ān to you as a gradual revelation tanzīlan is the predicate of inna ‘assuredly’ in other words We have divided it into parts instead of not revealing it all at once.