The concept of “sin,” as understood today, is not found in the Torah. It is an irrational concept that does enormous psychological damage to people.
The current concept of “sin” is a stain upon the soul that requires a kind of supernatural atonement or cleansing process. In the Hebrew Bible, wrong behavior is seen in a rational, natural way. Scripture speaks of three categories of wrongs that are not synonyms. There is chet, the misstep, literally meaning “missing the mark,” as if one were shooting an arrow and hitting the outer rims of the target and missing the shooter’s goal, its center. The Bible mentions it 34 times. The second pesha, occurring 93 times, is a conscious rebellious act such as taking revenge, stealing, murder. The third avon, cited in 233 instances, is an error, an unintentional act that nevertheless has harmful consequences. Understood in this natural way, it should be clear that the misdeed is something that shouldn’t provoke passive feelings of guilt and prayerful recitations, needing clergy or a psychiatrist to erase it. Individuals should recognize what they did wrong, think why they did the wrong, take actions that remedy the consequences, and assure that there will be no repetition.
The New Testament describes Jesus retaining this understanding of resolving wrong behavior by physical acts. Jesus is quoted as saying in Matthew 5:17 and 18 that he did not come to change the law. “Do not think that I came to abolish the law or the prophets. I did not come to abolish but to fulfill. For truly I say to you, until heaven and earth shall pass away, not one dot will pass from the law until all is accomplished.” In the Greek, the word for “dot” is “iota,” which is Greek for the Hebrew tenth letter yud, which is the smallest letter in the Hebrew alphabet, just a little larger than a dot with a short tail.
Paul, who did not know Jesus and who brought his understanding of Jesus’ message to non-Jews, wrote that Jesus taught that converts to Judaism must obey the Torah. He was an observant Jew. He wrote in Philippians 3:6, “As to righteousness under the law, I am blameless.” In Romans 3:31, he said, “Do we nullify the law by this faith? Not at all. Rather, we uphold the law.” He, like Jesus, attended the temple and he made no statement that contradicted the three-part biblical understanding of wrong behavior. Paul’s main message, a message of the Torah, was to turn away from idols. Paul, who felt he must convert pagans, opposed circumcision for “gentiles-in-Christ” since he was not converting them to Judaism, only having them accept the teachings of Jesus, but if the convert wanted to become fully Jewish – for Christianity at the time was a branch of Judaism – circumcision was necessary even as it is required of all other Jews.
The second century Christian thinkers agreed. Valentinus (around 130) defined “sin” in his “The Gospel of Truth” as “a function of ignorance,” “error,” a mistake. Marcion (around 140) and Justin Martyr (around 150) agreed. As Justin Martyr wrote in Trypho 141, sin is when someone does something “contrary to right reason.”
When then did Christianity change? It did so with Augustine (354-430). Contrary to Jewish teachings that God is good and God’s creations are good, as stated in Genesis 1, Augustine taught that people are born with the stain of sin, an ingrained disability; people left to their own devices, without God’s mercy, can only sin.
Rather than seeing the story of Adam and Eve as an allegory, as Maimonides did in his Guide of the Perplexed 1:2, Augustine accepted the tale as historical reality and gave it a new twist: Adam was the originator of sin. Augustine believed that Adam had all humanity in some special way in him. His sin, according to this mystic view, was his descendants’ sin – they sinned when he sinned. After Adam human became defective: people functioned with a diminished capacity, unable if unassisted by divine grace to achieve the good. Humanity was condemned. In his City of God 13:23, Augustine wrote, the “inheritance of sin and death [is] conveyed to us by birth.” All people of all faiths are “part of massa damnata [the massive damnation], justly condemned because of Adam’s sin.”
God, according to Augustine’s new radical view, saves only a small part of humanity, not all, and he gives no idea why God selects some people and abandons others to hell because of Adam’s sin. Augustine’s god is violently and arguably irrationally angry at sin and perhaps even God’s own creations, redeems only a small number of people, just enough to show divine mercy. God is no longer the creator of what is good, but is emotional and vindictive. Yet, Augustine adds, somehow in some unknowable way, despite punishing innocent people, God is just.
Augustine’s notion has been accepted by many people and has had a deleterious effect. It seems reasonable to suppose that psychiatry is an outgrowth of the acceptance of original sin’s notion that people should feel guilt and anguish when they do something they think is wrong, rather than accepting the ancient view that mistakes can be rectified by repairing what was wrong, such as apologizing for an insult one made, accompanied by a sincere desire not to repeat the act and by some kind of behavior that will assure no repetition.
Many Christians and many Jews who, living in a Christian culture have absorbed Christian ideas, have forgotten the biblical concept of wrong behavior, and call Augustine’s invention of “original sin” a mystery and an integral part of religion. But it is only a mystery because it is inexplicable, and it is not part of original Judaism or Christianity.
A tragic example is the philosopher, Rabbi Hasdai Crescas (c. 1340-c.1410) who wrote a book entitled The Refutation of the Christian Principles. He wrote the book because many Jews were murdered by Christian riots, including his only son. Jewish communities were destroyed and a host of Jews converted to Christianity to avoid future persecutions. As a leader of Spanish Jewry, he felt obliged to do what he could to return the converts to their faith. Yet, without realizing what he was doing, he included the Christian idea of original sin in his Light of the Lord. He states that Jews were absolved of the original sin when they were circumcised. This idea about being absolved was also a Christian teaching – that prior to the appearance of Jesus circumcision saved the Jews from the impact and punishment of the original sin. Some other rabbis in the Babylonian Talmud, Avodah Zarah 22b, Shabbat 145b–146a, and Yevamot 103b also accepted this notion.
 This is the rational understanding of Maimonides in his Mishneh Torah, Hilchot Teshuva.