Answer to an Old Article

Just about a year ago, I wrote a series of articles for Catholic365.com on the subject of The Trinity. That series is, of course, still available in my archives here and is much more extensive than this article is intended to be. Part of what motivated this writing was a revisiting of the original, specifically the first one titled “Introduction to the Trinity”.
One of the failings of this site, unfortunately, is that we don’t get alerts when someone makes a reply to an article. However, the response in this case was just posted a few days ago, and my reply there forms the core of this article. The person, who is named “Anthony”, wrote the following:
“The creed of Jesus in Mk 12:29 is Unitarian, agreeing with a fellow Jew. The Lord our God is one Person, or One Lord. Daniel 3:17 in the LXX defines God as "our one Lord." That is one Person. Single personal pronouns define the one God thousands of times. God in the NT means the Father 1300 times. Paul repeats the Unitarian Shema of Deuteronomy 6:4 in I Corinthians 8:4-6.”
Apparently, the responder is a non-Catholic, for he espouses a doctrine declared as heresy by the Church nearly 1700 years ago. “Unitarianism” was the belief that God is a single Being in Person rather than in substance. It denies the Deity of the Lord Jesus Christ, reducing Him to a created being and reduces the Holy Spirit to an impersonal force.
Modalism, which is the belief that God is a single entity filling different roles in various stages of His dealing with mankind (The Father in creation, The Son in redemption and the Holy Spirit indwelling believers today) is one form of this error. I sometimes compare it to an actor in some ancient play who portrays different characters in the same play by means of different masks worn during the play. This is the theology espoused the Oneness Pentecostals today.
Arianism is another form of it. This error is held by the Jehovah’s Witnesses in our day and teaches that the Lord Jesus was not God but rather the Archangel Michael prior to the incarnation. In fact, they go so far as to doctor John 1:1 to make the Lord not THE God but “a god”.
Why Does It Matter?
It matters because if the “Jesus” that one follows is not the Jesus of the Bible: the Son of God, co-eternal and co-equal with the Father and the Holy Spirit, then there is no salvation in such a one. If Jesus is not “God incarnate” then He is unqualified to pay the price for our sins. Saint Paul makes it abundantly clear that mere sacrifice of a creature is incapable of making atonement (read Hebrews). The Old Testament Law forbids human sacrifice… in fact, God used Israel to judge the nations around them who practiced that. Jesus must be God or He cannot be savior.
Flawed Definitions
One of the tricks used by Unitarian proponents is that they misstate what the Doctrine of the Trinity says. They define the word "person" to equal the term "entity" so they end up thinking that the Trinity says that "There is One God and three entities (or beings)" If we were to say that then it would be polytheism. As I said in the article, that is not the way that we use the term. The word "person" as used in theology is a means of expressing the relationship which the Scripture clearly shows exists within the Godhead.
Ignoring Scripture
Proponents of such theology love to trot out carefully selected verses of Scripture that they believe support their view while ignoring the teaching of the panoply of Scripture on the subject… much of which refutes their error. To pervert the nature of God to fit personal theology one must overlook all that the Scripture says about the following points:
1. The Father is God
2. The Son is God
3. The Holy Spirit is God.
One cannot deny the Deity of either the Son or the Holy Spirit without denying all the Scripture that supports these claims.
4. The Father has mind, will and emotion
5. The Son has mind, will and emotion
6. The Holy Spirit has mind, will and emotion.
No one can see all the verses that teach these facts and deny the Personhood of either the Father, the Son or the Holy Spirit
7. They are distinct from one another, as can be seen when:
a. The Son prays to the Father,
b. The Son says He was sent by the Father
c. They refer to one another in the third person singular (He)
d. The Son and the Father send the Holy Spirit.
e. The Father spoke at both the Baptism of the Lord and at the Mount of Transfiguration. The Holy Spirit appeared at the Baptism according to the eye witness account of Saint John the Baptist.
An excellent article that examines these facts in detail (beside my own series listed above) is: “The Trinity (Tri-unity) of God” on the Bible.Org site. Although not a Catholic site, I think they do an excellent job on this subject.
Conclusion
There is no other formulation of the nature of God than "The Trinity" that doesn't violate one or the other of these scriptural FACTS.
Proof texting that gives any interpretation of the intent of the author that violates these FACTS is private interpretation. For instance, to interpret "echad" in Deuteronomy 6:4 as only meaning a numerical "one" rather than a "oneness of unity" violates everything else that the Bible says about the nature of God... to wit all the points I listed above.