It may be more helpful to start with monotheism, and follow the developments as they occurred. First, there was the Israelite experience, which left the Jews with the firm conviction that there was only one God, and to say otherwise was directly against His command (Ex 20:3). Nothing else was to be worshipped (Ex 20:4-6). The existence of other beings who might claim the title of god was acknowledged at first (Ps 82), but increasingly it was recognized that the idols worshipped by surrounding nations were no more than metal, wood, and stone (for example, Isa 40:18-26; 44:6-20, Jer 10:1-16, Hos 2:18-20). At the same time there was in-creasing recognition of a supernatural power opposed to God (Job 1,2; 1 Chron 2 1:1; compare 2 Sam 24:1).
Then along came Jesus.1
|1At this point I can hear some objecting that we cannot use the Gospel accounts in a straightforward way. But that is exactly what being an authoritative source means. The burden of evidence is on those who would deny the validity of that authority. And it is nonsensical to invoke a doctrine of no miracles as evidence against the authority of the Gospels in view of our previous discussion.|
|2The title Son of David (Matt 9:27; 12:23; 15:22; 20:30-1; 21:9,15, Mark 10:47, Luke 18:38-9) is also a Messianic title (Matt 22:42, Mark 12:35, Luke 20:41).|
|3In some circles it is fashionable to deny that Jesus used the title Son of Man. This is done on an artificial division of Matt 26:63-4 and Mark 14:61-2 (Luke gives a slightly different version), and Matt 10:23, Mark 8:38, and Luke 12:8-9, under pressure to separate Jesus from supernatural claims. But it must make major revisions to the Gospel story It ignores the clear implications of several passages (for example, Matt 9:6; 20:18,28, Mark 2:10, Luke 9:22; 19:10, John 3:13-4; 5:27) and the direct identification in Matt 16:3.|
|4But the Son of Man would. See Dan 7:14. Some versions use the word “serve”, but the Aramaic word used here is used exclusively of religious service in the Biblical record.|
|5But Matthew draws from it the lesson that God had delegated forgiveness of sins to men, presumably in general, in 9:7.|
How does one deal with these facts? One can deny that Jesus knew what He was talking about. This is what the leaders of Judaism did, and the majority of the Jews apparently followed them. I find it hard to dismiss Jesus’ claims that easily. Nobody back then, even of His enemies, disputed His miracle-working power; rather, they attributed it to the Devil (Matt 12:24, Mark 3:22, Luke 11:15). His raising of the dead can be passed off as initial mistaken diagnosis in most cases, but Lazarus was apparently starting to decompose (John 11, esp. v. 39). In some ways even more miraculous is the healing of the man born blind (John 9). If eyesight is not restored within a few years of birth, a blind baby loses the ability to have an appropriate response in the retina and/or brain to light stimulation, so that even if you replace the lens or cornea, the child remains blind. This means that Jesus could not have just repaired this man’s corneae. He had to somehow rearrange the man’s nervous system, and do so while leaving his sense of self and personality intact. Finally, if Jesus was not the Messiah, then the Jewish nation (and the world) is still waiting for the Messiah, as no one else of similar stature has appeared before or since. As John 7:31 puts it, “When the Messiah comes, shall he do greater works than this man?”
On the other hand, Jesus claimed to be one with the Father. This would seem to leave the option that Jesus was in some way to be identified with God. Jesus seems to have done that Himself when He said, “Before Abraham was, I AM” (John 8:58), “He who has seen me has seen the Father” (John 14:9), and “I and the Father are one” (John 10:30).6
|6Although too much should not be made of the last statement because of Jesus’ defense of it in vs. 34-38 and his statement in John 17:21-23 that we are to be one as Jesus and the Father are one.|
Then on top of this we have the phenomenon of the Holy Spirit, which is spoken of in the singular. The early understanding of this seems to be that this is the same as the Spirit of God spoken of in the Old Testament, but in greater measure or able to do more qualitatively, or both. Thus the early church had to account for God the Father as ruler of the universe, Jesus Who was also God, and the Spirit inside of them Who was also the more or less direct influence of God. Some early formulas suggest that they had a Trinitarian view of all this (Matt 28:19, 2 Cor 3:17;13:14). 
This was the tack taken by the early Greek fathers. Their formula was one hypostasis (and later ousia), three prospa. This is usually translated one substance, three persons (from the Latin personna),7
|7Interestingly, the Latin personna was a face or mask as well. It is the English translation which is distorted.|
It might be added that something like this theory would be required if God is outside of time and Jesus is in time. It is conceivable that God would have written Himself into the script, so to speak, when He created the world of time and space. But that would mean that although this Person would accurately reflect His character, this Person would not exhaust all there is to God. If this Person died (which Jesus did), the universe would not grind to a halt or fall apart.8
|8This is not an easy concept to visualize. But that does not mean it is wrong. Quantum mechanics is difficult to understand. But it is still more correct than mechanical theories of matter. If there is another theory that is correct, then it is still stranger to our everyday experience. As C. S. Lewis observed, correct theology will he “at least as difficult as modern Physics, and for the same reason.” (Mere Christianity. New York: The MacMillan Company, 1943 (10th printing 1958), p. 121).|
The popular misunderstanding of this has been that Jesus, God the Father, and the Holy Spirit are sort of like three players on the same team, each with His role. Each is a person, that is, a distinct being, but they all have the same substance, that is, each is (so to speak) made out of God-stuff. This is simply tritheism. In effect it is little different from Arianism, and in fact the problem of Arianism is not the making of Jesus subordinate to the Father (after all Jesus did use the terms Father and Son to describe that relationship, a clearly hierarchical one) but making Him a separate God. This does not do justice to monotheism.
One reason this is important is that it explains the central importance of the life of Jesus in Christian theology. If you really want to know what God is like, the clearest, most accurate picture of God is to be found not in nature or even in the Old Testament, but in Jesus of Nazareth. And that is not only true of His teachings, but also of His life. From a Christian perspective, which I believe we have seen to be the most reasonable, the life of Jesus is the most important set of events in history. 
Another reason this is important is that there are theories which involve driving a wedge between Jesus and God. Perhaps the best-known example is a common explanation of the substitutionary theory of the atonement. Briefly, this theory states that God has made a law that everyone who sins must die. We have all sinned, and therefore we must all die. But Jesus offered to die for us, and God has accepted Jesus’ offer. So when our names come (or came) up in the judgment, and the Devil tries to point out our sins (some versions are base enough to make God “the accuser of the brethren”), Jesus pleads, “My blood, My blood,” and God says, “Well, all right, I’ll let this one in”, or perhaps He can’t even see our faults because He is too dazzled by Jesus’ righteousness. Jesus really pulls the wool over God’s eyes.
Now this model does explain some statements in the Bible. We have no room to boast about our own righteousness. There is some kind of judgment that goes on in heaven. And parts of the model do appear to have been used by the apostle Paul.
But it is not a perfect model. It is fundamentally flawed. For it pretends that Jesus is more interested in our welfare than God is, whereas the truth is that “God so loved the world that he gave his only son.” (John 3:16) That is what the Trinity means. “He who has seen me has seen the Father.” (John 14:9) God is every bit as interested in our welfare as Jesus is.9
|9The theory that God can’t see our sin because of Jesus’ righteousness is also fundamentally flawed because God is omniscient. God sees not only the sparrow fall but also the boy whose slingshot made it fall. Indeed if the implications of quantum theory are correct, He made the nerve impulses go to his forearms, and the tendons transmit the tensions that allowed him to pull back on the slingshot and then let it go, and moved the rock toward the bird in response. The same holds true for murdering humans, or any other form of lawbreaking.
God is also responsible for keeping alive the memories of such deeds, as He is for all memories. Thus if anyone, including the “accuser of the brethren”, remembers that something awful has been done, it is because of God. Thus God certainly does know how bad we have been. Perhaps the good news is that He loves us anyway.
What I am saying is that this view of the atonement is similar to Newton’s law of Gravitation. Newton’s theory explains a lot of things. It was once the best theory around. And it was rightly taught in physics books (and is still taught as an approximation). But it is not the way God thinks. This has partly to do with the exceptions, and partly to do with the fact that “simultaneous”  cannot be defined in a straightforward manner (for those who want more information, the clearest explanations come from Einstein himself). Similarly, this view of the atonement has good points. But it fails with the exceptions (which we will see later), and it makes assumptions which cannot be reconciled with trinitarianism, or for that matter, with the omniscience of God.
Thus, through a consideration of the relationship of Jesus to God the Father one can gain a new perspective on the way to ascertain God’s character, understand more fully the relationship of God to time, and avoid buying completely into an imperfect theory of the atonement.