Now when all the people were baptized, and when Jesus also had been baptized and was praying, the heavens were opened,
and the Holy Spirit descended on him in bodily form, like a dove; and a voice came from heaven, "You are my beloved Son; with you I am pleased."
One of the most unique, and misunderstood, doctrines of Christianity is that of the Trinity. Classical Christian doctrine teaches that we serve one God, and within that one God there are three distinct and eternal persons: Father, Son, and Holy Spirit.
One of the first criticisms that is often heard against this doctrine is that the word "trinity" is not anywhere in the Bible. This argument is a canard, and can be easily dispelled. It is true that the word "trinity" is not in the Bible, but the Trinity is seen through the Bible (clearly in the New Testament, and hints of it in the Old Testament). Luke 3:21-22, cited above, is a an example where all three members of the Trinity can be seen in the account of the earthly life of Jesus.
Throughout it's history, the Christian church has been confronted with many misunderstandings of what the Trinity is. Some of these misunderstandings have led some to herecies to which the church as a whole had to come together to address and denounce.
Some have attempted to describe the Trinty through visual illustration that we see around us every day. There is the example of the chicken egg: 1. the shell 2. the albumen 3. the yolk. There is also the example of the experiment where scientist took a drop of water, put it in a vacuum tube, brought the temperature inside of the tube to a certain level, and observed that the drop of water was able to be water, ice, and steam at the same time. These types of illustrations can be very tempting in our trying to explain or teach the doctrine of the Trinity to another, but they should be avoided because there is no earthly example that can be used to try to understand what the Bible is teaching when it reveals the Trinity to us. Some of the illustrations that are often used could lead to a heretical understanding of what the Trinity really is.
The Christian church had to face one of these herecies in the third century in the teachings of Sebellius, a theologian. Sebellius taught that God had manifested Himself in three modes of a single devine Person. He taught that God manifested Himself as Father in the Old Testament, Son while Jesus was on the, earth, and Holy Spirit during the Church age. It is similar to me saying that I am a son, a husband, and a brother, but that is nowhere close to what the Bible teaches on what the Trinity is. Another name that has been given to this teaching is "modalism," the idea that God has had three faces or has worn three masks. This herecy has led to another heretical teaching known as "Patripassionism," the idea that God the Father died on the cross. Again, that is not the Trinity. Why do I focus on this herecy? Because, it is still taught in some cults that claim to be Christian. One of these where it can seen is in the teachings of ths "Oneness Penecostal" movement, and in the beliefs of one of their leading voices, Bishop T.D. Jakes. See if you can tell the subtle hint of Sebellianism in the "Belief Statement" of his church, The Potter's House, on the section about God:
"There is one God, Creator of all things, infinitely perfect, and existing in three manifestations: Father, Son, and Holy Spitit."
Again, this doctrine must be taught with care. A wrong understanding of this crucial doctrine can mean a difference between orthodoxy and herecy, and a difference of heaven and hell. Why is this so? Becuase, if we have a wrong view of God, and we are worshipping an idol of our own imaginations. (c.f. Romans 1:23) The last time I looked at my Bible that was a violation of the Ten Commandments (c.f. Exodus 20:3).