When the Bible was written there was no concept of original sin. I'm trying to figure out when this idea emerged. So far I have found that St. Augustine wrote about this first.
The idea of a ransom sacrifice is certainly difficult to swallow. Jesus death forgives sins yet the Bible also says our death forgives our sins. So, which is it? Judaism had no concept of sin.
After studying the Jewish culture about sin and looking into the NT objectively and the many theories of Jesus atonement and their history, I have found that the one that makes sense to is the Moral Exemplary theory.
Phillip Quinn explained it this way:
My suggestion is that what Abelard has to contribute to our thinking about the atonement is the idea that divine love, made manifest throughout the life of Christ but especially in his suffering and dying, has the power to transform human sinners, if they cooperate, in ways that fit them for everlasting life in intimate union with God. ... On [this] view, the love of God for us exhibited in the life of Christ is a good example to imitate, but it is not merely an example. Above and beyond its exemplary value, there is in it a surplus of mysterious causal efficacy that no merely human love possesses. And the operation of divine love in that supernatural mode is a causally necessary condition of there being implanted or kindled in us the kind of responsive love of God that, as Abelard supposes, enables us to do all things out of love and so to conquer the motives that would otherwise keep us enslaved to sin.