Exploring Sin and Salvation: Jesus vs. Paul

The Christian faith is rooted in the belief that Jesus died for the sins of the world and was then raised from the dead. But is this what Jesus himself preached during his public ministry? In the Gospels Jesus certainly predicts his coming death, on numerous occasions. But are those saying historical? How would scholars know? What is the evidence both ways? And if Jesus did not anticipate, let alone predict, his death, does that completely undermine the Christian faith?