When one does a search for first sin or first sinner, a multitude of articles come up about Adam. This is from the basis of belief over record, since God never refers to Adam as committing a sin. Sin is not mentioned until after the removal from Eden.
Adam and later Eve had the innocence of children throughout most of their stay in Eden. They were immortal beings who knew nothing of right and wrong until after they ate the forbidden fruit. Children and those with the minds of children are considered innocent by God, which would have included Adam and Eve.
The forbidden fruit is what enabled Adam and Eve to know right from wrong. God made it clear what would happen, but it was a foreign concept without the knowledge gained from eating the fruit. To say Adam sinned is no different than saying a child sinned, which has no basis in the Tanakh.
Children are innocent until they stop being children. Once adulthood sets in, at that point they become responsible and capable of sinning against God. The Bar/Bat Mitzvah in Judaism is going from child to adult, which is innocence to sinner.
Bereishit, also known as Genesis, 2:17 is generally translated as, “But of the Tree of Knowledge of good and evil you shall not eat of it, for on the day that you eat thereof, you shall surely die.” A closer understanding of what was written makes it clear death is not immediate, but a beginning through the aging process that would come later.
Adam, without the concept of a personal death, would not have understood the consequences. It was no different than telling a young child that a flame is hot. The words mean little to a child until they learn about the consequences. Without experiencing anything, it would have been impossible for Adam to understand what would happen after eating the fruit.
Bereishit 3 goes over the details of what happens following the eating of the fruit and removal from Eden. Not once is sin mentioned in regards to either Adam or Eve. The reason can be found in 3:5 and 3:22. Both refer to knowledge of good and evil lacking prior to the eating of the fruit. Without knowledge, no sin can be committed.
The first time sin is mentioned is Bereishit 4:7 in regards to Cain’s anger prior to the murder of his brother. It is not referred to as a sin to be angry, but to give in to the anger with what he intended to do. Cain had already intended to commit murder, which is why God made clear he had a choice and could rule over the temptation.
Bereishit 4:7 is not just the first mention of sin, but of free will. With the knowledge of evil, comes the knowledge of good. Cain was free to choose and his choice, according to 4:8, was to murder his brother. The moment he committed murder was the moment the first sin had been committed.
Knowledge of good and evil and free will are two of the many things that separate humans from animals. When a lion or lioness kills a cub, it is no different than a lion or lioness killing anything else. A lion or lioness knows only nature and acts according to that nature, as all animals do with the exception of humans. Only humans can be held accountable for murder of humans, since the knowledge of good exists along with the free will to exercise restraint.
If Cain, not Adam, was the first recorded sin, why is Adam considered today? 2000-years ago, when the Wisdom of Solomon was written, it is clear that the belief of first sin lied with Cain.
Wisdom of Solomon 10:1 – 4
 Wisdom protected the first-formed father of the world, when he alone had been created; she delivered him from his transgression,
 and gave him strength to rule all things.
 But when an unrighteous man departed from her in his anger, he perished because in rage he slew his brother.
 When the earth was flooded because of him, wisdom again saved it, steering the righteous man by a paltry piece of wood.
The reason the first sin is no longer laid at the feet of the first sinner, Cain, is a misunderstanding of Romans 5:13 and 14.
- To be sure, sin was in the world before the law was given, but sin is not charged against anyone’s account where there is no law.
- Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a command, as did Adam, who is a pattern of the one to come.
There are no other references used to point to Adam. Without knowledge of good and evil, there is no knowledge of the law. Paul points out that Adam did not sin, but what is written is not what is believed by those who assume it says something other than what it says.