Here's another reason the JWs' "Word" the Christ can't be just a man and not created, and that he was, and is, God. It involves the Holy Spirit.
The baptismal formula at Matthew 28:19 reflects in one sentence the Trinitarian doctrine of three Persons as one by virtue of the singular “name” into which Christian believers are to be baptized. By means of logical deduction Christ must be eternal in accordance with the baptismal formula.
For example, the Jehovah's Witnesses would have Christians baptized under three distinct and separate authorities which is scripturally unfounded. If they were right, and the Son is separate from the Father, the Holy Spirit must also be separate from the Father, but that in turn would imply that the Father was without His electrical current or authority and He is not all powerful. If, on the other hand, the Holy Spirit is inseparable from the Father then neither can the Son be separate from the Father because Christ is the Spirit.
To illustrate further, Paul taught at Romans 8:9-11 that the Spirit of God is the Spirit of Christ and 2 Corinthians 3:17 teaches that Jehovah God (or the Lord) is the Spirit (NWT; “the Lord is the Spirit” RSV). And, it is this Spirit, the Holy Spirit, that dwells within the Christian believer. Thus, there are not two separate Spirits that reside within, God’s and Christ’s, but one Spirit, according to Ephesians 4:4.
There is one body and one Spirit, just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of us all, who is above all and through all and in all. (Ephesians 4:4-6)
But you are not in the flesh, you are in the Spirit, if the Sprit of God really dwells in you. Any one who does not have the Spirit of Christ does not belong to him. But if Christ is in you, although your bodies are dead because of sin, your spirits are alive because of righteousness. If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ Jesus from the dead will give life to your mortal bodies also through his Spirit which dwells in you. (Romans 9:8-11 RSV)
Jehovah is the spirit. (2 Corinthians 3:17 NWT; “the Lord is the Spirit” RSV)
However, if, as the Jehovah's Witnesses falsely teach, the preexistent Christ is a created creature only, then the Holy Spirit must also have been created and accordingly there would have been a time when there was no Holy Spirit and therefore God would have lacked power and authority and would not have been omnipotent, according to their theory. But, since the Holy Spirit is eternal, which the Jehovah's Witnesses must concede, and the Spirit of God is the Spirit of Christ, and this Spirit is the Holy Spirit, Christ the Word must be eternal.
Not surprisingly, the Jehovah’s Witnesses changed Romans 8:10 by inserting the word “union,” so that Christ is not in the believer, but only in union with the believer, writing: “But if Christ is in union with you, the body indeed is dead on account of sin …” NWT).
http://144000.110mb.com/trinity/index-6.html#27