Jesus lived and died a Jewish Pharisee. He exhorted the Jews to return to the ways of the Jewish scriptures. He was a righteous man who lived poor and loved the poor. But he called the hypo-critic Jewish elite 'white washed tombs' and 'sons of serpents.' At the instigation of the Jews the Roman procurator Pontius Pilate crucified Jesus as a public nuisance in Jerusalem. Many felt that the poor guy wouldn't have to suffer so ignominiously and some of them started thinking Jesus was suffering for their sins. St Paul, moved by the vision of a 'cross-carrying bleeding Christ,' asserted he had suffered for the sins of others. Slowly the doctrine of redemption was on a solid foundation. So was the foundation of a new religion based on that doctrine. Christianity had its beginning in Paul's brain. Poor Jesus had not ever thought of any such development in his life. He was content being a Torah-abiding Jewish preacher-critic.
In the whole of the Old testament we do not find anywhere any plan of Yahweh to redeem man from his original sin. We come to know about god's plan of redemption only after St. Paul constructs his above theory. The Roman crucifixion of an ordinary Jew gets a new meaning. How can a punishment meted out by the rulers of the time become atonement for the sins of mankind?
If God really wanted to help man he could have avoided sending the foolish test after creating the first parents. Instead, He sent the wily serpent to tempt Eve and as desired by Him they failed. For that momentary disobedience God started roasting their souls in eternal fire. He is not moved by their painful screams and cries for help. Is it just to burn man in towering flames for all times for a small disobedience in his temporary life? How can that God be love? Even if he wanted to wash away the original sin, a nod of His head or little finger was more than enough. Will anyone send His only son to get tortured, scourged, beaten and crucified as atonement?
Yahweh the god of the Jews, who had freed the Israelite from the Egyptian slavery and settled them in Canaan after massacring thousands of soldiers of the kingdoms of Canaan and traveled with them in the desert in an arc, and protected them like a fiend later turned against them. He instigated the newly formed Christians to persecute His own people! God's selected tribe, the people of Abraham, with whom Yahweh had entered into a covenant got rejected and discarded as enemies.
God forgot his covenant with Abraham and his insistence on circumcision: his new followers could keep their foreskin and they simply had to get washed in water in His name. The whole thing makes ample sense.