Two of the most difficult doctrines in the Bible are the two-fold nature of Jesus Christ as both God and man and the doctrine of the trinity of three persons but one God. The doctrinal formulas were formed over centuries and they have seemed to hold to the tests of time and controversy. They take the clear teachings of scripture and put them together into a form that brings seemingly contradictory teachings into a unified doctrine. They are truly orthodox.
Let us look at the doctrine of the trinity. The teaching is that there are three persons of the Godhead, but there is only one God. This is based on three teachings of scripture:
- There is one and only one God (Deuteronomy 6:4; Mark 12:32).
- The Father, the Son, and the Holy Ghost are distinct persons.
- Yet all three are God.
As I said, these statements seem to contradict one another. That is the reason for the three-in-one God. He is a trinity--or tri-unity. "For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one" (1 John 5:7).
You ask about illustrations and suggest a man who has three roles: father, husband, and father. The problem with this illustration is that it is of one person with three roles. I am afraid that it might lean toward the Apostolic Church teaching of three consecutive roles for God: first as Father, then as Son, and finally as Holy Ghost. However, you will find that all illustrations of the trinity fall far short of describing the real thing. Here are some of which I am familiar:
- An egg with yolk, white, and shell.
- An old-fashioned tire with tire, tube, and air. (I don't even know how many people would understand this one today.)
- A pie cut into three pieces.
- Water in its three states: solid, liquid, and gas.
There is one illustration that I think has biblical backing (although it has drawbacks as well). It is man himself and this illustration is only slightly different from the one you suggest. Man was made in the image and likeness of God (Genesis 1:26-27). Although I do not have undeniable proofs of this, I believe that the "image" has to do with the basic form of man's being and "likeness" has to do with basic qualities such as a sense of justice, an appreciation of beauty, an understanding of love, and other things.
If I am correct about the image of God in man, this refers to man being a three-in-one being just as God is a three-in-one being. Man is made up of spirit, soul, and body (1 Thessalonians 5:23). The body is that part of man which is seen. This matches Jesus Christ, the Son of God, as the only person of the Godhead to be manifest in the flesh. The spirit of man matches the Spirit of God. The soul of man is the center of control and matches much of what is said in scripture about the Father.
Man is certainly NOT three persons in one being. However, his body, soul, and spirit have some form of independent existence. Death occurs when the spirit and soul leave the body. Yet, men commonly refer to a person being buried in a certain place--though it is just his body. And people speak of how good someone looks at the funeral home. Also, the Bible refers to the souls as being the people themselves. In Revelations 6:9-10, the souls of those who have been slain are seen and they cry unto God for vengeance. In Luke 16:24, the soul of the rich man in hell speaks and mentions his tongue. And, finally, the spirits of men also have some sort of independent existence. By comparing Ecclesiastes 3:21 with Ecclesiastes 12:7, we see that the spirits of men return to God in heaven after they die.
Yet, even though each part of man has a form of existence apart from the other parts, man is not fully complete unless all three parts are combined into one person. And, although the three persons of the Godhead seem to operate separately and distinctly, they work in perfect harmony and are one. There was a time when they separated. The Son proceeded forth from the Father (John 8:42) and the Spirit proceeded forth from the Father and the Son (John 15:26). There will also be a time when they come back together in full unity. 1 Corinthians 15:28 states, "And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all."
In the same way, the three parts of man may be separated for a time. But there will also be a time when the three will all be joined together again. This is called the resurrection.
Now I do not claim to have a full understanding of these things. They are too high for me. But the Bible clearly teaches them. It is up to us to take God at His word even when we do not fully understand Him. As to using man to illustrate the trinity, it is weak but it is the only illustration I can find that God gave as such. It will have to do until we can begin to see God Himself more clearly.