Addressing people according to their level of understanding in the Holy Quran

﴿وَمَآ أَرۡسَلۡنَا مِن رَّسُولٍ إِلَّا بِلِسَانِ قَوۡمِهِۦ لِيُبَيِّنَ لَهُمۡۖ فَيُضِلُّ ٱللَّهُ مَن يَشَآءُ وَيَهۡدِي مَن يَشَآءُۚ وَهُوَ ٱلۡعَزِيزُ ٱلۡحَكِيمُ ﴾ [Ibrāhīm: 4]

(4) And We did not send any messenger except [speaking] in the language of his people to state clearly for them, and Allah sends astray [thereby] whom He wills and guides whom He wills. And He is the Exalted in Might, the Wise.

Surah: Ibrāhīm - Verse: 4 - Juz: 13 - Page: 255

﴿وَلَوۡ جَعَلۡنَٰهُ قُرۡءَانًا أَعۡجَمِيّٗا لَّقَالُواْ لَوۡلَا فُصِّلَتۡ ءَايَٰتُهُۥٓۖ ءَا۬عۡجَمِيّٞ وَعَرَبِيّٞۗ قُلۡ هُوَ لِلَّذِينَ ءَامَنُواْ هُدٗى وَشِفَآءٞۚ وَٱلَّذِينَ لَا يُؤۡمِنُونَ فِيٓ ءَاذَانِهِمۡ وَقۡرٞ وَهُوَ عَلَيۡهِمۡ عَمًىۚ أُوْلَٰٓئِكَ يُنَادَوۡنَ مِن مَّكَانِۭ بَعِيدٖ ﴾ [Fuṣṣilat: 44]

(44) And if We had made it a non-Arabic Qur'an, they would have said, "Why are its verses not explained in detail [in our language]? Is it a foreign [recitation] and an Arab [messenger]?" Say, "It is, for those who believe, a guidance and cure." And those who do not believe - in their ears is deafness, and it is upon them blindness. Those are being called from a distant place.

Surah: Fuṣṣilat - Verse: 44 - Juz: 24 - Page: 481