"Indeed, We have sent it down as an Arabic Quran," meaning: in an Arabic tongue, "that you might understand," meaning: so that you may understand what is in it and thereby believe.
﴿إِنَّا أَنزَلْنَاهُ قُرْآنًا عَرَبيا﴾ أَيْ: بلسانٍ عَرَبِيٍّ ﴿لَعَلَّكُمْ تَعْقِلُونَ﴾ لِكَيْ تَعْقِلُوا مَا فِيهِ فَتُؤْمِنُوا
