Surah Al-Isra 17:106

وَقُرْءَانًا فَرَقْنَـٰهُ لِتَقْرَأَهُۥ عَلَى ٱلنَّاسِ عَلَىٰ مُكْثٍ وَنَزَّلْنَـٰهُ تَنزِيلًا

And [it is] a Qur’ān which We have separated [by intervals] that you might recite it to the people over a prolonged period. And We have sent it down progressively.

Translation: Saheeh International

Tafsir

And it is a Qur’ān qur’ānan is in the accusative because of the verb governing it which is the following that We have divided that We have revealed in portions over 20 or 23 years that you may recite it to mankind at intervals gradually and with deliberateness so that they are able to comprehend it and We have …

Excerpt from Tafsir al-Jalalayn, commentary on 17:106, via Quran.com. The reader has the full commentary and 9 more tafsirs.