It seems to be a phenomenon of God before creation and during creation that just like a person can be a mouthpiece for another person so the Logos was like a mouthpiece for God, expressing God the Father in the way the Son alone could do because He fully knew the Father. As a person's word has all the characteristics of that person so the Son of God has (and had and will have) all the characteristics of God. Hence the Son is divine and in the greatest sense anyone save God Himself can be.
