‘Umar bin al-Khattab wrote to Abu Musaa [May Allah be pleased with them both] and said,

أما بعد, فتفقهوا في السنة و تفقهوا في العربية و أعربوا القران فانه عربي

“To proceed, learn the Sunnah, learn Arabic, and learn the Qur’an in Arabic for surely it is Arabic.”

Source: Sharh Iqtidaa as-Siraat al-Mustaqeem pg.345 [Official print from the Mu’assasah ash-Shaykh Muhammad bin Saalih al-‘Uthaymeen al-Khayriyyah]