Muslims believe that the word of Allah has always existed eternally in heaven. It is the uncreated word of God that came from him.
Then Allah sent it down to earth as a revelation to mankind.
It was written down in human words and printed on paper so that man can see it, touch it, revere it, read it and understand it.
What was heavenly became earthly when it was confined on to the pages of a book. What was divine came among humans so that humans can receive it and perceive the words of Allah.
If the Quran remained in heaven, man would never be able to know the word of Allah. And even though it looked like any other book, it was Allah's book.
Jesus is The Word of God. (John 1:1-3)
He has always existed eternally in heaven as the divine Word of God. He was one with the Creator, and the uncreated Word of God.
Then God sent His Word down to earth as a revelation to mankind.
The Word took on the nature of a human being. (John 1:14)
The divine became a man so that man could see him, touch him, revere him and understand him.
What was heavenly became earthly and confined in a human body so that man can know him and receive him. What was divine, came among humans so that humans can receive and perceive the Word of God.
If the Word had remained in heaven, we would never be able to know Him fully and completely. Jesus himself said that he has come down from heaven. (John 3:13). And even though he looked like any other man, he was the Word of God.
Muslims, you can believe that the eternal and uncreated word of Allah from heaven came down to earth, was incarnated in human language, and confined to the pages of a lifeless earthly book called Quran.
But you cannot believe that the eternal and uncreated Word of God, Jesus, came down from heaven, was incarnated in human form, and was confined in a living earthly human body, and He was called Jesus.
"For God loved the world so much that he gave his one and only Son, so that everyone who believes in him will not perish but have eternal life. God sent his Son into the world not to judge the world, but to save the world through him." John 3:16-17, NLT
Who Is Kalimatullah?
Can God Become Visible?