I was asked the following question by "Noor," who commented on my Mark 9:1 post:
"I really want to know why you believe that God had become a man and died for our sins ...every time I've asked this question ..people explain how it's supposed to work..saying 'God is pure and we are sinners so someone has to die for our sins.' They fail to understand that this is an explanation and not a proof. I understand how it's supposed to work but what I want to know is why do you believe that God has to die for our sins ..the question is Why and not How..if you know what I mean."
The best I can do if I understand the question correctly is refer to those authors who have established the case for the resurrection of Christ, which is the culmination of His saving mission on Earth and the verification of his own stated claims that he is the son of God, son of man and Messiah. (If I blog about the Resurrection myself, I would only be duplicating their work.)
The book I'm most familiar with that proves this was written by Dr. Gene Scott, "Jesus Christ, Super Nut or Super Natural!" There is a condensed version of his case for the Resurrection and Godhood of Jesus, preached as a sermon on an Easter Sunday, at http://www.gospeloutreach.net/resurrection.html. Other classics in this vein include "Who Moved the Stone" by Frank Morrison, Fairbain's "Christ in Modern Theology," D.W. Forrest's studies on Christ, Sherlock's "Trial of the Witnesses," Paley's "Evidences for the Christian Faith," Nathaniel Lardner's studies of ancient history linking verifying evidence to the Gospels, and C.S. Lewis's "Mere Christianity." And no, I haven't read all of them, Dr. Scott's persuasion was adequate for me, even though I did read "Mere Christianity."
I'm told there is an author named Lee Strobel who wrote a book called "The Case for Christ." I've never read it, but it's one of the latest in a panoply of books that have been written that prove that Jesus Christ said things about himself impossible to believe or credit unless he backed it up with miracles only God could work, and then further prove that he did those works (including being raised from a death by Roman crucifixion after 3 days dead in a guarded sepulcher and ascending into a cloud 40 days later) and thereby proved he is God in the flesh.
There is also an article in the New Advent Encyclopedia that outlines the pagan and Jewish sources that confirm the validity of the Gospel sources for the life of Christ, found at http://www.newadvent.org/cathen/08375a.htm. And not to be forgotten, as background evidence to support the antiquity and authenticity of the New Testament, there is F.F. Bruce's classic study "The New Testament Documents: Are They Genuine?" And I'm sure there are many others that one can find out there.
My only point here is that I believe in Jesus Christ because he was proven to me to be the Lord God, not because of a feeling or a rhetoric laden, emotionally evocative Sunday morning harangue, but because there really is findable historical evidence that logically validates the Gospels' story about him. You don't have to cut the top of your head off or suspend belief in science or good scholarship to be a Christian, and at least some of these authors, including Gene Scott, started out as skeptics and were convinced along the way by the evidence.