In Matthew 12:38ff, the Pharisees asked Jesus for proof of God's working in him. Jesus responded by saying that the only real proof would be his death, burial, and resurrection.
I reckon that holds true for today also; if Jesus was not raised from the dead, then his teachings are irrelevant. But if he was raised from the dead, then he is who he said he is.
This seems to me to be the crux of conversion of Muslims, Hindus, Jews, atheists.
Was Jesus physically brought back to life after being executed? That is the question. (And I believe the answer to be "Yes".)