All translations are imperfect. The Koran contains some translations. Therefore, the Koran is imperfect. For example... But said Christ: "O Children of Israel! worship Allah, my Lord and your Lord." (Koran 5:72 AYA) Do you think Christ spoke Arabic or that perfect translations exist? For example, the word "Yisrael" has three meanings in Hebrew and thus, there will need to be the same number of meanings in Arabic for Allah to perfectly translate this word. And not to mention its etymology. The word "Yisrael" means "prince of God" in Hebrew but what does that word mean in Arabic? I would like to see which of the two premises above you can refute.