In case anyone is interested in this sort of thing, here is a list of names of teachings (with short explanations) that have sprung up over the years (concerning the Godhead) that are considered to be heretical (to one degree or another) by the church.
Trinitarian Heresies
Modalism (i.e. Sabellianism, Noetianism and Patripassianism)
...taught that the three persons of the Trinity as different “modes” of the Godhead. Adherants believed that Father, Son and Holy Spirit are not distinct personalities, but different modes of God's self-revelation. A typical modalist approach is to regard God as the Father in creation, the Son in redemption, and the Spirit in sanctification. In other words, God exists as Father, Son and Spirit in different eras, but never as triune. Stemming from Modalism, Patripassianism believed that the Father suffered as the Son.
Tritheism
...Tritheism confessses the Father, Son and Holy Spirit as three independent divine beings; three separate gods who share the 'same substance'. This is a common mistake because of misunderstanding of the use of the term 'persons' in defining the Trinity.
Arianism
...taught that the preexistent Christ was the first and greatest of God’s creatures but denied his fully divine status. The Arian controversy was of major importance in the development of Christology during the fourth century and was addressed definitely in the Nicene Creed.
Docetism
...taught that Jesus Christ as a purely divine being who only had the “appearance” of being human. Regarding his suffering, some versions taught that Jesus’ divinity abandoned or left him upon the cross while other claimed that he only appeared to suffer (much like he only appeared to be human).
Ebionitism
...taught that while Jesus was endowed with particular charismatic gifts which distinguished him from other humans but nonetheless regarded Him as a purely human figure.
Macedonianism
...that that the Holy Spirit is a created being.
Adoptionism
...taught that Jesus was born totally human and only later was “adopted” – either at his baptism or at his resurrection – by God in a special (i.e. divine) way.
Partialism
...taught that Father, Son and Holy Spirit together are components of the one God. This led them to believe that each of the persons of the Trinity is only part God, only becoming fully God when they come together.
Finally (just FYI), the church carefully formulated the Doctrine of the Trinity to circumscribe and safeguard the truth that the Bible teaches us concerning the Godhead (~not~ to explain it, because that is simply beyond us). The Trinity is considered to be one of our Biblical "mysteries", meaning that we know that it's true because the Bible tells us that it is, even though we are incapable of truly comprehending it/comprehending the true nature of the Godhead (and we never be, at least not on this side of the grave anyway).
It should be noted that the doctrine of the Trinity has been put to the test by millions of church doctors, theologians, pastors and knowledgeable laity year after year for millennia now, yet it remains one of the principal doctrines of the entire Christian church (IOW, of every church that falls within the pale of Christian orthodoxy, Catholic, Orthodox and/or Protestant, incl Baptist, Lutheran, Anglican, Methodist, Presbyterian, and all the rest).
God bless you!
~Deut
p.s. - we are, of course, free to believe whatever we want to believe, but when the historic Christian church, ~all of it~ (which spends so much time arguing and bickering over our differences, as you know) stands as ~ONE~ on a particular topic/teaching, I would think that alone would be reason enough to give those who question the validity of this doctrine pause to consider it again
Deuteronomy 6
4 Hear, O Israel! The LORD is our God, the LORD is one!
Genesis 1
26 God said, “Let Us make man in Our image, according to Our likeness; and let them rule over the fish of the sea and over the birds of the sky and over the cattle and over all the earth, and over every creeping thing that creeps on the earth.”
27 God created man in His own image, in the image of God He created him; male and female He created them.
John 1
1 In the beginning was the Word, and the Word was with God, and the Word was God.
2 He was in the beginning with God.
The mystery of the Godhead is indeed great, yes
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