The question of the nature of Jesus Christ - was he God, or was he a man? - caused a lot of ink to be spilled in the first centuries of Christianity. Even when they thought they had an answer - he's both! The minutia of how he could be both, as well as the ramifications of the various theories, occupied Christian leaders for centuries, when it could be argued that they certainly had better things to do.
The problem that the Church Fathers identified was that there were sections of the gospels and epistles that very clearly indicated that Jesus was a man, a very holy man, a special man, but a man - not God. There were also others which just as clearly came down on the side of Jesus being God. These second century scholars had a choice: they could ignore the question and focus what Jesus preached and encourage people to follow his example and live their life as he taught; they could decide that Jesus being a man made more sense and interpret the verses that suggested that he was also God in that light; or place their bets on Christ's divinity and interpret the verses that said otherwise in that light. What they did was decide that Jesus was man and God. They argued interminably about the details, but ended up with the conclusion that he was fully God and fully man. (The nuances of that stance take up fat volumes - check it out some time). They created a theological edifice to explain away a contradiction - which cannot be found in any actual book of the Bible.
A very large plot hole in the Bible is the stark difference between how God is portrayed in the Old Testament and the New Testament. (Other than the Apocalypse of John [Revelation] which reverts back to the wrathful, vengeful God imagery). In the 1800's there arose a theological position called "dispensationalism" which attempted to explain the differences. But long before that, Marcion, a second century Christian, came up with his own solution. Marcion took a blunt force approach to Biblical criticism and simply threw out the parts he thought made no sense. Observing that the vengeful God of the Old Testament bore no resemblance to the God of the Gospels he concluded that they weren't the same God. In Marcion's view, the Old Testament God was evil, while the New Testament God of Jesus was the "true" God. He threw out the Gospels of Matthew, Mark and John and the non-Pauline epistles and heavily edited what was left. Say what you want, but Marcion took care of those pesky contradictions!
Nineteenth Century dispensationalists eschewed Marcion's approach. Rather than relegating the Old Testament God to second deity status, they arranged history as outlined in the Bible into a number of "dispensations". A dispensation, according to them, was a time period where God dealt with humanity in different ways from the other time periods. There were usually seven of these time periods, although I have seen eight listed as well. Since these dispensations were the opinions and interpretations of the theologians who came up with them, there were difference ways to divide them up. Here are a few ways that people have attempted to assign the breaks in these divisions:
- Innocence/Original Paradise/Garden of Eden - Adam and Eve before eating from the Tree of Knowledge
- Conscience - after "The Fall" - no rules, people followed their own conscience, ended with The Flood
- Human Government - From Noah to Abraham - not sure how this differed from the previous
- Promise - starts with Abraham and indicates God dealing with one specific group of people - ends with Moses
- For some, the previous three are grouped together, sometimes called "patriarchal"
- Law - the giving of the Law to Israel - different interpretations on when it ended
- Christ's Ministry - not all recognized this - some interpretations ended Law at Jesus' resurrection, some at the beginning of his ministry, some at the ascension, other at the end of The Acts of the Apostles. The Christ's Dispensation likewise had differing opinions on it's scope, or even if it is a separate time period
- Grace - this started whenever either the Law or Christ dispensation ended and includes the present day.
- Tribulation - starts with the rapture and includes all the horrors of the Book of Revelation
- Millennial - ends with Christ's return to defeat The Beast and The Devil and initiates the Thousand Year reign of Christ on Earth
- Some combine the previous two
- Paradise - establishment of God's eternal kingdom on earth
Despite there being disagreements among Christians on where these divisions should begin and end, the concept is logical. There's no question that God acts differently throughout different time periods as outlined in the Bible. But there are no bright lines delineating changes in God's rules - if there were, there would be no disagreement among the various advocates of dispensationalism. This is the problem with viewing the Bible as an inerrant and divinely inspired, it's impossible to accept that there are errors, discrepancies and contradictions and one has to sometimes tie oneself into knots to make it make sense.