The following is based on the presumption that the reader is a Christian, or a seeker after Truth! If the reader is not one of these, and is one of those people that wish only to debunk, or attempt to destroy faith in God and His Christ, then they should read no further, as there is no comfort for them in the following, they must await Rev. 20;15, which will be after they die!
The so called “original sin”, was committed in Genesis, when Eve “ate of the fruit of the tree of the knowledge of good and evil” followed by Adam, (Gen. 2:17), (Gen. 3:13). This is often misquoted, as “the tree of knowledge”, which is the same sin as Satan in Gen. 3:4. The point is that Adam and Eve DISOBEYED God, they then for the first time perceived good and evil, with the consequences for the human race ever since, in this Creation! The Age of the Earth Controversy:
The definition of sinning was not given until The Law was given to Moses on Mount Sinai. The Law was given at that time to the Jewish race only, and only they were subject to it, which the Apostle Paul elucidates in His Epistles. In the period from the Law being given to the 1st advent of Jesus, the Jews were given precise sacrificial rulings for the expiation of their sinning. The Lord gave confirmation of this in Matt. 11:13.
John the Baptist, was the “forerunner” of a change. He baptised for the expiation of sin, which infuriated the Jewish Priesthood. Jesus confirmed that John’s baptism was valid, and used that occasion to show that He (Jesus) would baptise with “The Holy Spirit”! Christ’s death Sacrifice on the cross at Calvary, covered both elements of the Sin question, the fall of Adam and Eve, and sinning in the lifetime of a person.
That Jesus came initially “to the lost sheep of Israel”, is without question (Matt. 15:24), but as He was rejected by the Jews, both before Pilate and after Paul’s extensive work with the main Synagogues, at Acts 28:28 the Gospel of Salvation in Christ Jesus was sent to all the world’s peoples! This act of rejection by the Jews, in the wisdom of God opened up the possibility of a huge harvest of regenerated people for The Godhead, which was the desire by God from the beginning. Israel have been put on one side temporarily, (Lo-ammi), and this present time, (Age time) is for the world’s peoples to either accept or reject Christ!
If a person accepts this great Salvation, they are perceived as sinless in Christ. Their sins in life are forgiven when confessed to Christ. Any that are un-dealt with by the individual, are resolved at the meeting of Christ and His Body. Only He knows the heart of a person, and only He knows what is True!
The seeker after Truth may well ask why this question of "Sin" is so important to the working out before Almighty God of its consequences and its resolution in the Body of Christ Jesus on the cross of Calvary. That subject is dealt with in the following link. Satan's Motivation: