While the Christian belief in God as Trinity is most profound, it is also most complex and can only be accept by faith. There are many humans who cannot accept this idea of God, especially many monotheists. They refuse to believe and accept something they cannot understand. Of course, as I always say, if we only accept those things that we can understand there is no need for faith. Faith means believing in those things I cannot understand as truth.
Although difficult to understand, Gregory Nazianzen wrote that THREE is a name which unites things united by nature, and never allows those which are inseparable to be scattered by a number which separates. Two is the number which separates, three the number which transcends all separation: the one and the many find themselves gathered and circumscribed in the Trinity. He wrote:
When I say God, I mean Father, Son and Holy Spirit; for Godhead is neither diffused beyond these, so as to introduce a multitude of gods, nor yet bounded by the small compass than these, so as to condemn us for a poverty-stricken conception of deity, either Judaizing to save the monarchy, or falling into Hellenism by the multitude of our gods.
St. Gregory is not seeking to vindicate the trinity of persons by human reason. He simply shows the insufficiency of any number other than three. But we may ask whether the idea of number can be applied to God. St. Basil replies:
We do not count by addition, passing from the one to the many by increase; we do not say: one, two, three, or first second and third. For I am God, the first, and I am the last. Now we have never, even to the present time, heard of a second God; but adoring God of God, confessing the individuality of the hypostases, we dwell in the monarchy without dividing the theology into fragments.
As you can tell, the Holy Fathers of our Church, in putting forth the idea of God as Trinity, addressed a multitude of objections, even to the fact of using the number three as being very unique. The Church has defended vehemently the mystery of the Holy Trinity against the natural tendencies of the human mind that finds it incomprehensible. While we say that there are three Persons in God, there is still only one God.
What do you believe about God?