While I was happily and attentively supplicating Allaah The Almighty, I laid down the Book of Allaah before me and prostrated before it in the direction of the Qiblah (direction of prayer). I did so while I was thinking that is the exalted words of Allaah The Almighty. Later I feared that this deed may be an act of Shirk (polytheism); we seek refuge with Allaah The Almighty from this. Would you please clarify the Sharee'ah ruling on this?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Principally, we are commanded to glorify the Mus’haf  (the printed copy of the Quran) by way of reading and acting according to its teachings, not to prostrate before it. However, as long as you did this out of fear of Allaah The Almighty and due to ignorance about the Sharee'ah ruling, you incur no sin, Allaah willing.

In this context, it was reported on the authority of Abu Hurayrah the Prophet, sallallahu ‘alayhi wa sallam, informed us that a person who had never done any good deed asked the members of his family to burn his body after his death and to scatter half of its ashes over the land and the other half over the sea. He feared that if Allaah The Almighty gathered him, He would severely punish him and so he commanded them to do this out of his ignorance that Allaah The Almighty would indeed be able to gather him despite this. When that person died, his family did what he had commanded. However, he sallallahu ‘alayhi wa sallam, added, that Allaah The Almighty commanded the land to collect the ashes scattered over it and He commanded the sea to do the same, and both of them did.  Subsequently, Allaah The Almighty questioned him about the reason behind his deed and his answer was that he did so due to fear of Allaah The Almighty. Therefore, Allaah The Exalted forgave his sin. [Al-Bukhari and Muslim]

Commenting on the Hadeeth, Ibn Taymiyyah mentioned that this person was ignorant about the Omnipotence of Allaah The Almighty to gather the parts of his body and he hoped that He would not return him to his previous state. However, when he had belief in Allaah The Almighty and His Command, forbiddance, promise and punishment and was also ignorant without having sufficient knowledge to be judged as a Kaafir (disbeliever), Allaah The Almighty forgave his sin. Many Muslims are similar to this man. In this regard, it is important to note that the Prophet, sallallahu ‘alayhi wa sallam, used to talk about the earlier people of the previous nations so that the individuals of this Ummah (nation) may be deterred.  

Allaah Knows best.