The word translated as “Word” in John 1 is the Greek word logos, and is a reference to Christ  The Greek speaking world understood this word to refer to more than just “word.”  It included the concepts of expression, wisdom, reason, and order.  Jesus, whom John has in view when using the word in John 1, is the exact expression of the Father (Heb 1:3). He is the agent of the Father, and He performs the Word of God. There is salvation through no other channel.  In the OT, salvation was through faith in the sacrificial system, which pointed to Christ.  In the NT, salvation is through faith in Christ, the fulfillment of the sacrificial system.  Natural theology (discerning the existence of God through the creation) is not a means to salvation. Salvation requires regeneration by the Holy Spirit (Titus 3:5), and relies upon the presentation of the gospel (Rom 10:17).  I would agree that most of the OT verbal communication of “God” was via the second person of the Trinity (Christophanies, rather than simply theophanies, as Timothy Ward suggested), including the voice in the burning bush on Sinai – note that Jesus claimed to be that voice when He said, “Before Abraham was, I AM.” (John 8:58). The Exodus text itself sates that the voice was the angel of the Lord and yet spoke as God in the first person.  Who can be both the angel (deputy) of God and speak as God in the first person, but the preincarnate Christ?  Lastly, when we speak the Word of God, we do not have authority, but the Word does.  The Word is Christ.