At John 17:1, 3 Jesus prays to the Father: "FATHER, .... this is eternal life: that they may know you, the only true God, and Jesus Christ whom you have sent." - New International Version (NIV). Here the Father alone is not only very clearly identified as the only true God, but Jesus Christ is again pointedly and specifically excluded from that identification ("AND Jesus Christ whom YOU [the only true God] have sent"). (Also see: How do we know that Jehovah the Father is God alone? and Why does the Bible phrase Jesus as a separate person from God?)
Jesus' words here are in harmony with what the Bible says about the Father being Jesus' God: "Blessed be the God and Father of our Lord Jesus Christ". (1 Pet.1:3) Jesus said, "`I am ascending to my Father and YOUR Father and to my God and YOUR God.'" (John 20:17)
Some claim that the import of John 17:1-3 can be ignored because Jesus said this as a man on earth. But even in heaven, Jesus refers to HIS God and the name of HIS God. (Rev. 3:12) (Also see: How can Jesus have a God and be God at the same time?)
Some make the claim that for the Father to be the "only true God" at this scripture, then that must mean mean that Jesus is a false god. But the title "the true God" does not have to mean that there are no others who may be called "gods" or "a god" in a subordinate but righteous sense. It is, however, an exclusive title for God, the Most High, only true God, Jehovah. And clearly it refers exclusively to the Father. No one else is the God or the True God. (Ps. 86:10; 2 Kings 19:19; Is. 37:16.) (For more, see: If the Father is the "only true God" (John 17:3), does that mean that Jesus is a false god?)
One more thing to consider:
Jesus said in John 17:3 that it means everlasting life to know God (the Father) and also Jesus. So if the Holy Spirit really is God, then why isn't the Holy Spirit mentioned here as well?
This would be an unforgivable slighting of the True God if the holy spirit were truly a person who is God (or 1/3 God, or anything else trinitarians want it to be), but it would be exactly what would be expected if the only true God were the Father alone (Jehovah alone), and if the Christ and savior were Jesus alone, and if the holy spirit were not a person but God's active force and therefore had no personal name or identity. (Also see: If the Holy Spirit is God, then why isn't the Holy Spirit given equal description in the Bible?)
For more, see:
Examining Trinity 'Proof Texts'
Search For Bible Truths - ARCHIVE
Search For Bible Truths - Search Guide