Qur'ān 19:97 · Maryam (مريم)

فَإِنَّمَا يَسَّرْنَـٰهُ بِلِسَانِكَ لِتُبَشِّرَ بِهِ ٱلْمُتَّقِينَ وَتُنذِرَ بِهِۦ قَوْمًۭا لُّدًّۭا

So, [O Muhammad], We have only made Qur'an easy in the Arabic language that you may give good tidings thereby to the righteous and warn thereby a hostile people.