Surah Yusuf Tafseer

Verily, We have sent it down as an Arabic Qur'an in order that you may understand.

The Arabic language is the most eloquent, plain, deep and expressive of the meanings that might arise in one's mind. Therefore, the most honorable Book, was revealed in the most honorable language, to the most honorable Prophet and Messenger, delivered by the most honorable angel, in the most honorable land on earth, and its revelation started during the most honorable month of the year, Ramadan. Therefore, the Qur'an is perfect in every respect.

So Allah said,

نَحْنُ نَقُصُّ عَلَيْكَ أَحْسَنَ الْقَصَصِ بِمَا أَوْحَيْنَا إِلَيْكَ هَـذَا الْقُرْانَ وَإِن كُنتَ مِن قَبْلِهِ لَمِنَ الْغَافِلِينَ