The trinitarian nature of God has always been a challenge for Christians. It was a challenge for the church to settle on and formulate the doctrine in the fourth century. It has been a challenge for the church to keep a firm grip on this doctrine in each successive age. Most recently, it is the Russellites, the so-called Jehovah's Witnesses, who have embraced the Unitarian heresy. But American Evangelicals, in their theological shallowness and self-centered sentimentality, have a dangerously weak grasp of this essential doctrine.The doctrine of the Trinity is challenging because though Scripture clearly teaches the doctrine, albeit indirectly, it is a doctrine that is uniquely incomprehensible. In fact, my theology professor in seminary, Wayne Spear, told us, "If you think you understand the Trinity, you're a heretic." Then he would smile mischievously. Some people have tried to explain the Trinity with pictures and diagrams--think of Saint Patrick and his cloverleaf--but ultimately they attempt to simplify what cannot be simplified without being utterly falsified.
This may lead some to wonder if the doctrine is even true? Of course, a re-engagement with the witness of Scripture should be sufficient to draw the doubting soul back to the Father, Son and Holy Spirit, saying "Where else will I turn, Lord? You have the words of eternal life." But As Moses was not able to look at God directly, but instead viewed him indirectly, seeing only his hind parts, so too, though the Trinity may be impossible to understand fully when studying it directly, it may be helpful to examine it indirectly by asking, "What if God were not a Trinity, a tri-unity, one God in three persons?"
Consider three doctrines concerning God as he has revealed himself in the Bible. He is trinitarian, i.e., he is one God and yet he exists in three persons. He is self-sufficient, i.e., he does not need us or anything else in his creation. He is love, i.e., he is essentially relational.
If God were unitarian and essentially relational, he would not be self-sufficient. That is to say, he would suffer loneliness apart from his creation. He would need us. But that is absurd. That would not be a God worthy of worship. That would be a God with whom you could negotiate an eternal bargain. Conceivably the human race could form a labor union of sorts and conspire to withhold fellowship from God unless he met our demands. The very thought of it is blasphemous. I once heard a minister tell his congregation that God created us because he was lonely. Of course, because God is indeed trinitarian, Father, Son, and Holy Spirit were perfectly content in loving friendship with one another before the creation of the world. Loneliness was impossible. How could any mere creature rival what the three persons of the Trinity had, continue to have, and always will have with one another? Clearly this minister of Christ was not accustomed to thinking about what came out of his mouth when he instructed his people in their faith. But that notion of God's neediness that only we can fill is very attractive to those who are self-centered and sentimental and thus have little concern to be Biblically theological.
Alternatively, if God were unitarian and wholly self-sufficient, then he would not be love. That is, entering lovingly into relationships would not follow from his essence. He could remain cold and aloof from his human creation, issuing only laws and demands while punishing every infraction with a severe hand. Of course this is Allah, the god of Islam, who is nowhere in the Koran identified as "love."
Both of these absurd consequences are grotesquely unchristian. You cannot be a unitarian--i.e. deny the existence of the one, true God as tri-unity, Father, Son, and Holy Spirit--and believe coherently in a transcendent God who is nonetheless a loving God.
