Fussilat - 41:3

كِتَـٰبٌ فُصِّلَتْ ءَايَـٰتُهُۥ قُرْءَانًا عَرَبِيًّا لِّقَوْمٍ يَعْلَمُونَ

A Book whose verses have been detailed, an Arabic Qur’ān1 for a people who know,