TH offers the proper rebuttals to the justification for the veracity of the God-Man, Christ's own claims. C.S. Lewis wrote in
Mere Christianity:
"A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic - on the level with a man who says he is a poached egg - or he would be the devil of hell. You must take your choice. Either this was, and is, the Son of God, or else a madman or something worse. You can shut Him up for a fool or you can fall at His feet and call Him Lord and God. But let us not come with any patronizing nonsense about His being a great human teacher. He has not left that open to us."
The existence of such a large body of historical and archeological evidence, including from those who were openly hostile to the existence of Christ, supporting descriptions from Scripture lends weight to the book's authenticity. That this book contains numerous descriptions casting many prophets and disciples in a very poor light suggests that the book is not a whitewash or false legend-making attempt. No one questions the works of Plato, Aristotle, Herodotus, or Tacitus, yet the number of copies of these works that survive dates many hundreds of years after their assumed original authorship, and even then, only few copies exist. Compare that to the thousands of complete manuscripts of books of the Scripture that exist, some dated to within 50 years of Christ's death.
That so many (thousands) who were actual witnesses to the life of Christ and His ministry coupled with the many who followed Him to their deaths speaks to the fact that He was not just a great teacher or that He was a delusional schizophrenic. To suggest that this was some kind of mass delusion, would mean it was (and continues to be) the greatest example of mass delusion recorded in human history.
That the tomb was indeed found empty speaks to His resurrection, for any reasonable person would conclude that there is no way the local religious and Roman authorities would have allowed an insurgent group of fanatics to sneak in and spirit away Christ's body, given what was at stake. Indeed the authorities would have wanted to parade the body of Christ before the crowds of these so-called 'fanatics' to deride them and prove that He was just a man. Scripture also tells us that hundreds actually saw Christ after His death. Given the variety of circumstances under which these witnesses saw Him, no one can claim that this was some kind of mass hallucination.
That Christianity had spread to nearly five million persons by the time of Paul's death also gives strong evidence that something other than rumor was afoot. Myths and legends take hundreds of years to develop. The ministry of Christ could not have been mere legend given its rapid spread and the formation of Christian creeds within less than ten years after the death of Christ.
History records no example of anyone claiming to be the incarnation of the one and only invisible God come down to earth. All other religions, Hinduism, Buddhism. Confucianism, Shintoism, and Islam, were founded by human beings. They find their basis in man-made philosophies, rules, and societal norms for behavior. Remove the founders of these religions and little would change. Remove Christ from Christianity, and nothing remains. Christianity is not a life philosophy, a religious life of ritual, nor a mere ethical standard of living. Christianity is based upon a knowing, assenting, and trusting relationship with its resurrected Founder. Therefore such a claim by Christ must be taken to be either delusional or factual. It cannot be both. Either Christ was exactly who He claimed to be, or He was mentally disturbed.
The issue with the alternatives TH has responded to is not which is possible, for it should be clear that all three are possible. Instead, the vital question is which are the more probable? Deciding upon the identity of Christ is not just some idle intellectual exercise.
To claim He was a great moral teacher is not a logically valid option, given Christ's own claims of who He was. Thus we are left with Christ as either a liar/lunatic, or our Lord.
C.S. Lewis had it correct. Was Christ Liar or Lord? No one who is intellectually honest would opt for the former. Given the above, that leaves only one, obvious, Occam's Razor simple, answer.