The law suggests two kinds of sin; that of the flesh, and that of the will. Eve chose to follow her instinct; it looked good, it smells good... rather than the word of God. We share the instinctive nature with animals, but we are more than animals. By instinct, we choose good and evil for ourselves, giving no thought to it at all as we usurp God's position. God alone declares good and evil.  But by acting as though we are were God, we become his enemies; not acknowledging that He is God nor giving him thanks. We choose things for our own benefit and as we do, we send out ripples of pain, suffering and death. Sometimes our own ripples hit us, and we know the cause.Sometimes our ripples hit someone else, and they may or may not know the cause.Sometimes our ripples join someone else's ripples , and the person they hit has no idea where they came from. For this reason, our works are as filthy rags. We may choose to feed the poor believing it to be a good thing, where someone else feeds the poor because God says it is a good thing. Our work is not acceptable to God because WE chose it while pretending to be God. It didn't matter what God says about it, and it is only a coincidence that he thinks it is a good work too. It is the pretending to be God that makes us an enemy of God and our works worthless.  Instinctive sin can become rebellious sin when we become aware of it and choose to continue in it.