The fact that the Quran is in Arabic is mentioned in several verses of the Holy Book, which indicates its importance. They include verses 113 of Surah Taha, 28 of Surah Az-Zumar, 37 of Surah Ar-Raad, and 12 of Surah Al-Ahqaf.
There is also Verse 2 of Surah Yusuf: “We have revealed it in the Arabic language so that you (people) would understand it.”
Thinkers and Quran interpreters have cited different reasons for the emphasis on the Quran being in Arabic.
One is the clarity of the Arabic language. Ragheb Esfehani in his Arabic philology book considers Arabic to be a clear and eloquent language and says that the Quran in Arabic clearly demonstrates the truth and clarifies falsehood.
The Arabic language spoken in Hijaz has many pronouns that differ in terms of numbers and gender. It also has many capabilities to convey the meaning with the fewest number of words and with maximum clarity.
Eloquence and articulateness are among other features that distinguish the Arabic language from other languages.
Moreover, it is the divine Sunnah that every messenger of God is sent to people to speak to them in their own language. The Holy Prophet (PBUH) was appointed to prophethood among Arabs, so the divine book he brings should be in Arabic.
God says in Verse 44 of Surah Al-Fussialt: “Had We sent down this Quran in a non-Arabic language, they would have said, ‘Why have its verses not been well expounded?’ Could a non-Arabic Book be revealed to an Arabic speaking person?”
A historical study of the Arabic language before and after the revelation of the Quran shows that Arabs living before the advent of Islam knew many rhetorical principles and some of them were so skillful that they judged poems and highlighted their weaknesses and strengths.
The Quran called on them to bring a Surah like that of the Quran but they failed to so and no one else ever since has been able to do it. This is proof for the eloquence of the Quran and a good reason proving that it is a divine book.