The cross and resurrection are the central message of the Christian faith. This is not some secondary add-on; it is what Christianity is about. This is why it is difficult to write it off as a legend that developed later. The idea that Jesus was just a great moral teacher is congenial to the modern mind. But if Jesus was just a great moral teacher, then we end up putting Him on the shelf with the rest of the great moral teachers, and He is largely irrelevant. In Jesus’ time there were plenty of rabbinical scholars, there were plenty of secular moral philosophers--He would have been lost in the crowd. There was a man named Apollonius of Tyana. He was what many people regard Jesus as being. He was a standard moral teacher, he had a few odd miracles attributed to him as incidental support for his teaching, and he vanished into obscurity. Because he was totally irrelevant. The truth is we do not need another great moral teacher. We have plenty of great moral teachers. The problem is, we do not live up to their teaching. Even if we claim that Jesus was the best and most perfect moral teacher, that does not help. As C. S. Lewis points out, if we cannot do mathematics, what good does it do to be taught calculus?
But this is not what Christianity is about. Christianity is about God becoming a man (John 1:1-18; Philippians 2:5-11; Hebrews 2:9-18), paying the price for our sin (1Peter 2:24,25; Colossians 2:13,14; 2 Corinthians 5:21), and validating this by rising from the dead (1 Corinthians 15:1-20; Romans 1:4; Acts 2:22-32). Therefore, the resurrection is the foundation on which Christianity is based. And it must be remembered that about thirty years after the fact, there were people being put to death by Nero for being Christians. Now people will die for a lie. It is unlikely they will die for what they know is a lie. But nobody will die for some vague legend that has not really developed yet. It must also remembered that, right from the start, Christianity had fierce critics. These critics came up with all sorts of theories to explain the resurrection. But the one thing they never said was that it obviously did not happen but the story just grew up over time. They claimed that Jesus did not really die and later revived, that the disciples stole the body, that the women went to the wrong tomb, and similar stories. These ideas do not fit the gospel accounts as we have them. But if we claim the gospel accounts were completely invented, we have to ask why no one called them on it. And if there was nothing to explain, then we have to ask why people came up with these theories in the first place. And the empty tomb still stands as evidence that Christianity really is what it says it is.