Sin is connected to law. Sin results when you disobey the law. If you disobey the law you are punished for your sin. On the other hand, sin in not imputed, where there is no law.
For example, it is not a sin to take a walk in the park on a nice summer day. If the local officials, one day, made a law that said, "no trespassing in the park during the summer", now a sin will appear if you take that walk. The behavior is the same. The law decides if it becomes a sin or not. If they repeal the no trespassing law, the following year, now there is no sin, if you take that walk. The power of sin is the law.
Forgiveness of sins implies that law, in general, has been repealed, because the state called forgiveness of sins brings one to the same place as though there is no law. If all law was repealed, there would be no defined sins. Forgiveness of sin is like one being exempt from the law, by being exempt for the attached sins. If the law said no trespassing, and you did this, but the judge; uncle Bob, forgives you, it like there is no law or sin for you.
In bible tradition, the tree of knowledge of good and evil is occupied by Satan. Knowledge of good and evil is law, since law differentiates and teaches us the difference between good and evil behavior. Satan in this tree; orientation, tells us this is not an optimized orientation. One big problem with law is humans make too many laws, often for their own personal and political gain. Some would like make it a sin, if a cow has gas. The farmer will be sinner for cows being natural if a law passes.
Another main reason law is not optimized is connected to the concept of original sin. Law is not made for the righteous person. Rather law is made for the sinners. Once a sinner finds a new angle to steal or abusive, a new law will appear to regulate the new behavior. Although this new law covers a loophole in the law, the new law requires everyone conform, as though everyone one is a potential sinner.
In other words, even if you would never do this, due to deep moral and ethical restraint, by accepting group obedience to that new law, you sort of admit you could and would do it. Accepting conformity to that law, even if you would not violate it, is the nature of original sin. Everyone being forced to obey the law, implies that culture assumes we all are have the potential to do all the sins defined by the entire law. Law, and group conformity, assumes the potential for sin is a default state for all humans; original sin. If not, certain people would be exempt, based on proven righteousness.
When Jesus forgives sins, everyone who was assumed to be sinners, by default, due to the nature of conformity to law, can now be treated with the dignity of righteous people, since sin is not imputed when law is made void. Forgiveness of sin, voids the power of the law; sin.
An ideal law system would exempt people, from the majority of law, if they have a proven history of good behavior. We already do this to some extent. Small children are not under all the laws of adults, until they become 18. Children are not considered full original sinners, until they become 18. We assume a level of innocence to many sins. When one is symbolically born again, and we receive forgiveness of sins, we go back to a symbolic state similar to early childhood, where sin is less imputed, due to less forced compliance to all adult law; original sin.
One extra consideration is, even if you can accept forgiveness of sins, the long term impact of law on the unconscious mind, can still cause a state called guilt. Guilt can appear even without sin. For example, you wrong a friend, but that friend forgives you. Your sin has been forgiven. However, one can still feel guilty, even though that sin is not imputed, due to the forgiveness.
It was very difficult for humans, conditioned to original sin, to give up law since guilt would often remain. One is forgiven, but they cannot forgive themselves. There is something that is called the sacrifice for guilty; future. The sacrifice for sins is not complete, without the sacrifice for guilt. This is why law continues to be restored.
