Wondering how do Christians of varying denominations approach or not approach the concept of the trinity? How do you rectify Jesus and God and the Holy Spirit being "one" or signs of the other or manifestations of one? Also how do you define each? Or do you reject it altogether? And on what basis (reason or biblical) do you reject or accept and understand it?
When it comes to the official position of mainstream Christian churches there is a pretty unanimous and universal consent, the only real difference will come when we get to the matter of the Filioque controversy: the Western Churches embrace the Filioque clause of the Nicene Creed, the Eastern Churches reject the Filioque clause--if you're unfamiliar I'll get back to it later in this post.
We speak of there being three Hypostases (translated either as "Persons" or "Subsistences" in English) and one Ousia (Essence, Being, or Nature).
The concept of ousia refers to being,
thing-ness; for example a tree's
tree-ness, or a rock's
rock-ness.
What a thing
is.
The concept of hypostasis is a bit more complicated as while its use in Christian theology is more well defined, it can mean a lot of things depending on context, for example it could simply refer to the sediment that falls to the bottom of a container of standing liquid, or it would be used basically as a synonym for ousia in a philosophical context. As a compound word it is the union of hypo (under) and stasis (to stand), a strictly literal translation might be "understanding"; in Christian theological use it refers to the concrete realness of the Father, Son, and the Holy Spirit. Which is to say: the Father is a concrete, real, actual Someone; the Son is a concrete, real, actual Someone; and the Holy Spirit is a concrete, real, actual Someone.
What this means is that the terms "Father, Son, and Holy Spirit" do not refer to a merely perceived distinction (like an actor putting on different masks in a Greek drama, or and individual person taking on different roles in relationship to different people, e.g. a man being a father, son, and husband depending on to whom he relates) but actual distinction: the Father is Father of and to the Son, the Son is Son of and to the Father, and the Holy Spirit is the Spirit of Father and Son. Thus there is actual distinction in the Hypostases, and thus actual relationship between the Three.
We then assert that the Three are One, because there is one Ousia, one Being. In the most traditional way of putting it:
The Father is God in and of Himself, the Son is begotten of the Father from all eternity, He is therefore God of and from the Father; we say the Son is "homoousios" with the Father (meaning, "of the same Being"); and the Holy Spirit proceeds from the Father [and the Son] (filioque) from all eternity, and thus the Spirit is of the same Being as Father and Son. We do not have three instances of the Divine Being, but one, which belongs uniquely to the Father but of which the Son and the Spirit share by their eternal relationship to and from the Father. That is to say, the Son is God
because the Father is God. This is not the same sort of thing as saying that I am a human being because my father is a human being; because I am an entirely different human being than my father, we are two completely different instances of "human being"--the Father and Son are instead the same Divine Being, the same God, without separateness, without division. We say they are
distinct but not
separate; indeed they cannot be separate because they are indivisibly One.
As noted, the one major point of disagreement exists with the question of the Filioque, a word added to the Latin translation of the Nicene Creed in the latter centuries of the first millennium; the addition of this word to the Nicene Creed and the bishop of Rome claiming the right to add it without the consensus of the entire Church did not sit well with the Eastern Church and her bishops who refused the use of the Filioque clause. This resulted in the bishop of Rome sending a bull of excommunication to the bishop of Constantinople in the year 1054, which effectively began the Great Schism resulting in the Roman Catholic Church in the West and the Eastern Orthodox Church in the East. The word filioque is Latin for "and the Son".
That said, Western and Eastern Christians have largely been able to get along much better in recent years and try and build dialogue over this issue, with a lot of work being done to find a middle ground, to see if there is an actual theological disagreement, or if we are largely just having an issue of semantics. To that end many feel that "through the Son" may be the best way to understand the filioque in such a way as to find common ground with the East. But this is a highly complex thousand year+ debate that has been going on in Christianity and can't be fully explored here.
Otherwise, since all mainstream Christian churches, regardless of denomination or tradition, embrace the Nicene Creed and the unanimous teachings of the early fathers as it pertains to this subject.
Individual Christian opinion may differ, largely depending on how well they were taught, if they were taught, and so forth. One problem I've often noticed (including myself when I was younger) was how poorly taught the doctrine of the Trinity is, resulting in many wrong descriptions, some being actually heretical.
If you want the most official statements available, then the Nicene Creed is the best in that regard; in the West we also have another creed known as the Quicumque Vult or Athanasian Creed which is fairly exhaustive on the matter. Though one of my favorite statements actually comes from a rather obscure local Spanish synod from the 7th century. The 11th Council of Toledo, dealing with the recent conversion of the Visigoths in Spain from Arianism to orthodox Christianity, put forward a rather robust confession of faith which you can find online here:
Toledo-11
Outside of some of the great ancient fathers of the Church such as St. Athanasius or St. Augustine, there is a small work by Catholic theologian Fr. Hans Urs von Balthasar titled
Credo which is a simply wonderful set of meditations on the Apostles' Creed that does a fantastic job also dealing with Trinitarian thought.
-CryptoLutheran