There is no other dogma so central to Christianity than the one the Catholic Church celebrates this weekend: that of the Holy Trinity. It is the building block upon which all Christian belief is constructed. We hold, always have, and always will hold that it is essential to defining oneself as Christian. It is not simply a belief in Jesus. It must also be a belief in what He taught; which is a belief in His nature, which is in the unity of the Trinity.
It is interesting to note for fundamentalists who hold to a “if it is not in the Bible I do not believe it” faith that the word Trinity is not found in the Bible, and neither is the concept of Holy Spirit being part of the Trinity or that Jesus is of the same substance of divinity as the Father or that Jesus was fully God and fully human from the first moment of conception or that He was one person with two complete natures or how those natures function . . . So neither the word nor much of the assumed dogma of the Trinity can be found in Scripture.
Some will argue that “it is illogical to claim that since the word "Trinity" is not found in the Bible that its concept is not taught therein. This kind of objection usually demonstrates a prejudice against the teaching of the Trinity. Instead, the person should look to God's word to see if it is taught or not.” Yet this is precisely the argument used in teaching against Purgatory. It isn’t a Biblical word so it is thought a Catholic invention. Yet the Church freely admits to completely making up the name but it did so to give a title to a reality that Christ and others give us in Scriptural teaching. We say very little about what Purgatory is other than it is a something most must go through before entering heaven for it is clearly taught that nothing unclean shall enter before God. Purgatory simply means that one is purged of their sins before entering heaven.
The teaching of the Trinity is becoming more of an issue recently as Mormonism is rises in notoriety. There is some debate between two camps that argue whether a Mormon is in actuality a Christian or not. (Not whether they are good people or not – but as to whether they can take the title Christian or not.) A recent NPR show had a woman who is a Mormon stated emphatically that she is Christian and will not allow anybody to tell her otherwise.
Here is the main point of debate taken from Fr. Z’s blog, “Gods, for Mormons, were mortals who became gods. Mormons hold that “God the Father” actually has a wife, a “Heavenly Mother”, with whom he procreated “Jesus Christ” who also acquired “divinity”. For Mormons, the “Holy Spirit” is also the offspring of parents. For Mormons, four gods guide the universe, three of whom form a sort of “trinity”.” In order to claim that they are Christian, one must completely redefine what the Tirnity is – much the same way that marriage must be redefined as something else before it can be applied freely to other forms of relationships. For further reading he recommends going here.
N.B. This is not a commentary on whether a person is qualified to be president or not. This is a post about the most ancient teaching of the Trinity and what it means to be a Christian,