Recently I had the opportunity to explain the doctrine of the Trinity to a class of adolescents.
Whoa. Explain the Trinity? How presumptuous! Easier to try to stuff the universe in a thimble than to expound the mystery of the inner life of the Ineffable One.
Mystery though it be, there is perhaps no teaching so central to Christianity than the Trinity. It represents the only adequate synthesis of the Biblical data and is absolutely crucial to a right understanding of God, Salvation, Humanity, and in fact the whole scheme of Christian doctrine.
Take for instance the issue of salvation. Christians have always proclaimed that Jesus Christ is the savior of the world. However only God can save us; therefore the Christ who saves us must be God himself. Yet from its beginning the Church was also aware that God was saving them, was with them in the presence of the Holy Spirit. In the Holy Spirit the early Christians realized that God was present with them, yet he was somehow a different person from the Father and the Son.
Some people have a hard time with the Trinity because of conspiratorial view of Church history. That is based more on ignorance of the facts and misinformation than anything else. The doctrine of the Trinity was not fabricated by some oppressive patriarchal Constantinian state-church hierarchy in the 5th century as is sometimes imagined. It was born in the church's worship in its earliest days. The Latin "Trinitas" was first used in the 200's but only to articulate the existing understanding that there is a distinction within God Himself.
I have run into people, Christians included, who look at the Trinity as some sort of logical contradiction. "You say God is one and God is three. That is impossible, that does not even make sense."
They seem to think this is something along the lines of the Hindu guru telling their disciples to "think of the sound of one hand clapping." That statement is a logical absurdity. Whatever its purpose in Hinduism, Christianity does not deal in logical absurdities. The God who created the universe with order is a God of order Himself.
There is a difference between an apparent paradoxes and absolute illogical statements.
Charles Dickens' Tale of Two Cities begins with the classic line, "It was the best of times,
it was the worst of times."
We recognize that Dickens is reasonable because the way in which it was the best of times is different from the way in which it was the worst of times. There is no contradiction in Dickens' phrase.
Similarly, when Christians say that God is one being in three persons, they are simply saying that the way in which God is One is different from the way in which God is three. He is not one being and three beings, He is not one person and three persons. He is one being and three persons. These are separate categories.
While this may be initially difficult to grasp it is not impossible verbal silliness like "a square circle" or something of that sort. The way God is One is his being or substance or essence. The way God is Three is in persons. Within the one "substance" there is an unfolding of three distinct "persons." These persons, traditionally called the Father, the Son, and the Holy Ghost are differentiated from one another. Though they all share the same essence, the Father is not the Son, the Son is not the Spirit and the Spirit is not the Father. There is then unity of being and plurality of personhood within the One God.
Now if all this seems abstract and mentally taxing just remember, it's just the beginning. We have only scratched the surface. Thinking about the Trinity should humble our proud but simplistic notion that everything about our Faith must be easy. There is nothing easy about contemplating the self-revelation of the interior nature of the Almighty. Nor should it be. A God whom I could easily and fully figure out would hardly be one I would want to worship. Yet I can, as far as my mind is able, understand something about Him. The better I know about God, the better I can know Him personally.