It is certainly possible that the New Testament writers worked together and concocted a plan to use a good man named Jesus, who had recently died, in order to gain power and influence for themselves. But just because something is possible does not mean that it is a reality. It is possible that there is an ice cream factory on Jupiter, but that does not mean that one exists. When we look at the New Testament claims of Christ do we see what looks like an elaborate deception concocted by several people? Or do we see that their behavior is more consistent with the idea that Jesus actually did do miracles and rise from the dead? It is the latter explanation that best fits the facts.
Following is a list of reasons why the conspiracy theory does not work.
It would require great coordination of events and writing over a long period of time.
First of all, in order for this conspiracy to work several people would have needed to get together and write documents that were not only inspirational but reflected accurate historical accounts, could stand up to cross examination, and agreed with each other sufficiently to avoid being exposed as a fraud. After all, if their stories and writings were contradictory, their conspiracy would fall apart. This means that there had to be large and sophisticated collusion and careful, deliberate fabrication over a long period of time since the New Testament documents were written over approximately a 50 year span. The writers would have to be very careful about who was named and what places were mentioned. Why? Because the accounts dealt with actual places and people and they would have to make sure it was all correct.
If these people wanted to gain power and influence by concocting a plan as grandiose as this, is it logical to say that they agreed to make up a story about this person Jesus, who was known to many people, and say things about Him that were not true, and then get people to believe that He had risen from the dead? Does it make sense that they would go against not only the Jewish system but also that of the Roman Empire, all so that they could try and gain power and influence in an area already dominated by two powerful cultures, the Jewish and Roman? Or is it more logical to say that they didn't conspire to deceive, but simply wrote and testified to what they saw? Doesn't it make more sense to say that they wrote what they knew, recorded the facts, the places, and the events and that it was all true and that that explains the New Testament documents better than anything else?
It would mean that the NT writers wrote about truth based on a lie
The writers of the New Testament used the words "true" and "truth" 170 times. They lived for the truth of what they believed and they died for it as well. They wrote about truth (Rom. 9:1; 2 Cor. 4:2), honesty (Luke 8:15), love (1 Cor. 13:4-8), integrity (2 Cor. 7:2), compassion (Col. 3:12), forgiveness (Col. 3:13), etc., and it was all based upon their love for and dedication to the truth of Jesus. They spoke against hypocrisy (Rom. 12:9), lying (Col. 3:9), jealousy (James 3:13), and selfish ambition (James 3:16). In fact, they lived according to their words. Does it really make sense to say that the NT writers deliberately conspired to misrepresent the truth and then go to great depths, even to suffer beatings and death, all while they were continuously telling people to believe in a lie? Add to this how they knew they would be persecuted for this alleged conspiracy of lies and we have serious problems explaining their behavior. It would make far more sense to simply acknowledge that they were telling the truth and that it was not a conspiracy to deceive.
It would mean that the conspiracy would have to survive cross examination
For the conspiracy to work, it would have to face cross examination. Remember, the gospels were written as historical documents mentioning places, people, and events. There certainly were many people who were still alive and who could verify and/or deny the miraculous events concerning Jesus. If you want to make a conspiracy work, you don't offer verifiable facts. Instead, you make up stories that cannot be verified but sound good. This is what Joseph Smith did when he began Mormonism. Nothing of his great cities and civilizations in the Book of Mormon have been verified since 1830 when he published his book of Mormon. Smith's religion isn't based on historical fact with verifiable locations and events. Instead, it is based on a story that cannot be verified. This is not the case with the New Testament books. The Gospels contained records of Jesus performing many miracles and eventually rising from the dead in Jerusalem. He was crucified at the hands of the Romans who were urged by the Jewish Sanhedrin. This was verifiable at the time especially since names and places are listed in the gospels and epistles. All anyone would have to do is contact those people (or check the court records) and go to those places to verify the accounts.
If it was all a conspiracy, then where are the contradictory accounts refuting what the New Testament writers claimed? The problem is that there are no contradictory documents known anywhere that attempt to refute the claims recorded in the Gospels. In other words, there is no contradictory evidence even though there were plenty of people around who could have written material contrary to the claims of the New Testament. After all, Pontius Pilate was named (Matt. 27:2), as was Herod, king of Judea (Luke 1:5), the high priest Caiaphas (Matt. 26:3), Elizabeth (Luke 1:57), Mary (Matt. 1:25), John the Baptist (Matt. 3:1), Paul the apostle a convert from Judaism (Acts 9), etc. Locations were cited: Damascas (Acts 9:10), Cyprus and Cyrene (Acts 11:20), Jerusalem (Matt. 16:21), etc. Also, claims of Old Testament prophetic fulfillment were made (see Prophecy, the Bible, and Jesus) and all people had to do was read the Old Testament to check. In other words, there were plenty of people, most of whom were still alive, and places to go to and check in order to expose the conspiracy. But we find no contrary evidence or writings concerning the miraculous events of Jesus life, death, and resurrection.
If there is no contrary evidence, no contrary writings, then does it make sense that it was all a conspiracy? Of course not. If it was a conspiracy, then where is the evidence for it?
It would mean the conspirators would have to face persecution
Undoubtedly, if the writers of the New Testament documents wanted to gain power and influence by writing about a new religious system that would go against the culture of Judaism as well as that of the Roman Empire, they most assuredly knew they would face persecution. We have to remember that the culture of the time was not beset with litigation and polite procedures. People often reacted irrationally and would spontaneously try to kill people (John 8:59). It also means that those who wrote the New Testament faced certain social, economic, and theological pressures.
In the Jewish culture the religion was intimately interwoven into the social and economic fabric. Anyone who would go against that system would knowingly risk starvation, mockery, beatings, ridicule, loss of family and friends, etc. This is not something to be considered lightly. Perhaps a single demented individual might consider doing such a thing, but how is it possible to get Matthew, Mark, Luke, John, Paul, Peter, James, Jude, Timothy, Apollos, etc. to all join in the charade, risk loss of family, reputation, economic stability, be persecuted and maybe even face death? Is this something that is rational to consider? Should we believe that they were all working together to deceive people so they could gain power, fame, and influence? It is simply extremely unlikely and full of problems as a theory.
It would have to explain Paul's Conversion
How did the Christian conspirators persuade Paul who was a devout Jew, educated in Jerusalem at the school of Gamaliel, (Acts 22:3), a Pharisee of Pharisees (Acts 22:3), and who was given letters of authority by the Jews to go out and arrest Christians (Acts 9:1-2), to become a Christian and thereby give up everything he had come to believe and stand for? Remember, Paul was a heavy persecutor of Christianity: "And Saul was in hearty agreement with putting him [Stephen] to death. And on that day a great persecution arose against the church in Jerusalem; and they were all scattered throughout the regions of Judea and Samaria, except the apostles," (Acts 8:1).
The most logical reason for Paul's conversion is that Jesus actually appeared to him on the Road to Damascus in Acts 9. It would take something pretty severe to cause Paul to abandon everything he had been taught his whole life and to not only convert, but to also advocate, and teach about the risen Lord Jesus -- and he did this for years before he was finally killed for his faith. So, how would the conspiracy theory account for Paul's incredible conversion and life long pursuit of proclaiming Jesus as Lord and Savior? If an adequately plausible explanation cannot be offered, then the simplest one is best; namely, that Jesus appeared to Paul on the road to Damascus and Paul was then converted.
There is a principle known as Occam's Razor. This principle states that generally the simplest explanation is the best. When we examine the facts about the New Testament claims is it simpler to say that the New Testament writers conspired over many decades to write about actual places and people in such a way so as to convincingly deceive thousands of people into believing that Jesus was the Messiah, fulfilled Old Testament prophecy, healed the sick, cured diseases, claimed to be divine, raised Lazarus from the dead, was crucified by Romans after enduring the religious court of the Sanhedrin, was buried, and rose from the dead or that it simply all happened and they recorded it? Which is the simpler explanation? Which requires greater faith?
Did the conspirators get what they were after?
Finally, if power and influence were sought by the New Testament writers, did they attain it? At best, what they have gained by such an elaborate hoax would have been influence in a small group of people who were outcasts in Israel as well as Rome. Remember, to get followers into Christianity meant that you went against not only the Jewish system but also the Roman system, not to mention being able to concoct a story that could stand scrutiny. Obviously the odds are extremely against such a thing.
Did they get what they were after? They were outcasts in their own society. They were beaten, ridiculed, accused of debauchery, jailed, beaten, and executed. If it was all a conspiracy, did they get the influence and power they were after? It doesn't seem so. Instead, it simply makes more sense to believe the New Testament than to say it was all a hoax.