Dalil

Quran Maryam 19:97

فَإِنَّمَا يَسَّرۡنَٰهُ بِلِسَانِكَ لِتُبَشِّرَ بِهِ ٱلۡمُتَّقِينَ وَتُنذِرَ بِهِۦ قَوۡمٗا لُّدّٗا

Translation

So, [O Muḥammad], We have only made it [i.e., the Qur’ān] easy in your tongue [i.e., the Arabic language] that you may give good tidings thereby to the righteous and warn thereby a hostile people.