sin vs. wrong action.
Sin: an immoral act considered to be a transgression against divine law.
Sin requires that there be someone who is sinned against. Divine law is handed down from a deity (or deities). This sort of divine personage is personal, and cares about what people do.. cares enough to command “thou shalt not,” and cares enough to punish those who transgress.
Without such a deity, there is no sin, because there is no one to be sinned against. An atheist might have a moral code, and believe certain things are wrong to do, but the atheist would not believe in sin. The agnostic might wonder whether or not there is a god to be sinned against, and probably not worry about it.
What is the difference between sin and wrong action? And where do I get the phrase “wrong action?” I will answer the second question first. I get the concept of right and wrong action from Buddhism. I am not a Buddhist, but am influenced somewhat by Buddhist teachings.
So, what is wrong action?
Wrong action is doing something wrong, but without sinning against anyone. Wrong action is simply action that brings negative consequences to oneself or others or both. If one believes in the interconnectedness of all things and people, then bringing about negative consequences against oneself is bring about negative consequences against all.
One does not need to believe in interconnectedness to understand wrong action. One need only pay attention to the effects of one’s actions. To be observant is to learn. If one takes a particular action, and is then mindful of the consequence of that action, one can learn what is right or wrong action. Or, one can simply consider the consequences of an action before taking action. We cannot always know whether the consequences of taking action will be bad or good. Sometimes we can be surprised. But when we are surprised, we can learn.
What is the benefit of right action? Positive consequence instead of negative consequence.
What is the benefit of avoiding sin? Same thing.. except.. there is an element of fear involved in avoiding sin – the fear of offending the deity, or impairing the relationship with that deity. And with sin, there is an element of guilt.
The only fear of wrong action is the fear of negative consequence. The only guilt is human guilt. People who don’t believe in any gods can still feel guilty. But, the feeling of guilt is different. It’s letting oneself and/or others down, vs. offending a deity.
It is possible to believe in a deity that is all loving and not at all judgmental.. a deity that is not offended by anything we do. Perhaps this is best. One can have a relationship with such a deity, and not feel like one has sinned. But will believing in such a deity cause one to behave badly, if the deity is not a moral authority? I suppose one could believe in a non-judgmental deity, and still subscribe to the concept of wrong action.
But does anyone believe in such a deity? The vast majority of people on this planet believe in gods or a god that hands down laws, and is very much concerned with human behaviour.
As for me..
I am agnostic. I have no strong belief in any deity that has a name, and that sits in judgment upon humanity. I do believe that maybe some sort of god or gods exist, but that it/they are part of all that is, or that the deity is composed of all that is, or that arises from all that is.
I have no strong belief in a personal god. It is very rare that I pray, and when I do, I just say a prayer to anyone good out there who happens to be listening.. if there be any good spirit or deity.
Since I don’t believe in any law-giving deity, I do not believe in sin. I believe in right and wrong action. I believe in trying to take action that brings about good consequences and avoid action that brings about bad consequences. When I end up doing something that turns out to be wrong action, I feel bad about it (I might feel foolish, disappointed in myself, or sad I caused someone else trouble, for example), and don’t like the negative consequences, but I don’t feel that I’ve sinned against anyone. The word “sin” is not a part of my vocabulary or belief.
For me, believing in right and wrong action, but not sin, takes the pressure off. I allow myself to grow and change and become more wise without feeling guilt or that I’ve offended some divine being. There is far less of a psychological or spiritual weight to carry.
I prefer to think of morality in terms of right and wrong action.
Wandering Spirit 
I know this was written several years ago. I just today came across this. The dictionaries definition of sin is wrongdoing according to many translations and also synonyms. So you are talking one in the same. We cause our own troubles by going against wrongdoings to ourselves and others. Those that do believe in the Divine sin was described as things we shouldn’t do based on natural laws. There are many throughout history that misinterpreted that God was plaguing us, but that is not so. We plague ourselves by holding on to offenses, thinking evil thoughts on acts on others, and so forth.
I’m writing about sin as defined by Christianity, not by your dictionary. According to Christian teachings, sin is an action that is not only wrongdoing, but is an action done against God. God is who is sinned against. According to Christian teaching, it is God who created the natural laws, and it is God, therefore, who is sinned against.
This is what I was taught from the time I was a young child, up until the time I stopped practicing Christianity, (for a variety of reasons I won’t get into, because I want to stay on topic), when I reached my mid-twenties. I went to churches of many denominations during my time as a Christian – Protestant denominations – and later studied Catholicism. In all the churches, I was taught that sin was an action committed against God.
Repentance: saying one is sorry for having sinned, and committing to not sin in the future. If sin were not against God, there would be no need for repentance, because repenting requires someone to submit repentance to.
In Buddhism, by contrast, especially the Zen tradition I was most interested in, there is no God to sin against – therefore wrongdoing is simply “wrong action.” I have never heard or read the word “sin” within a Buddhist context.
Regarding your claim of a misinterpretation of God sending plagues and so forth.. your belief that God did not send plagues and other misfortune .. Incorrect, according to the Bible. Here are some examples:
The story of Exodus: God sent plagues to punish the Egyptians, because the pharaoh would not let God’s people go. Start with Exodus chapter 7, and read on from there.
Also in the Bible, when the Children of Israel, the ancient Hebrews, disobeyed God, he caused them to be defeated in battle. You can read about an example of this in Joshua chapter 7. However, when the Israelites obeyed God, God granted them victory. (Joshua chapter 8).
Two Israelites, Dathan and Abiram (not to be confused with Abraham), who disobeyed God, died when God killed them by suddenly opening up a hole below them in the earth, and closing the hole after they fell in. Right after that, God sent fire, and killed 250 men. Numbers 26:9-10.
Shortly before this incident, God plagued the Israelites with serpents: Numbers 21:6.
Jonah: He was commanded by God to go to Ninevah. He got on a boat headed to the city of Tarsis instead. Tarsis was in the opposite direction. Once at sea, God sent a storm that almost sunk the boat. Jonah agreed to obey God to spare the others on the boat. God calmed the storm, sent a huge fish (the bible does not say “whale”) to swallow Jonah.. and you probably know the rest of the story. Point being – God took direct action – sending the storm, and the big fish. You can read this story in the Book of Jonah.
And then, of course, the most dramatic Old Testament example of God directly punishing people – the account in Genesis of the Flood. God wiped out almost everyone on the planet, even the innocent animals. Yes, according to the story, all the people except for Noah and his family were horribly evil, and brought the flood on themselves. True, but God still took direct action and sent the flood. You can read about the Flood in Genesis chapter 6.
If the Bible stories are true, and God really sent plagues and floods, then I don’t see why it would be wrong to believe that God still directly punishes people via natural disasters and other misfortune. Some people still believe God does this, some people do not. Who is to say whose interpretation is correct? This is a matter of opinion. But, according to the Bible, you are wrong about God not sending plagues and other punishment.
One last biblical example – the astonishingly horrible misery that is predicted to come at the End of Days – read the Book of Revelation.
(I don’t believe the stories are true, I believe they are myths. I also don’t believe in the biblical God either – my views on God are.. somewhat different. I wrote a post about my views, called “God By Any Name.” I’m using the biblical stories to point out that God did, according to these stories, send plagues and other disasters and punishments, and, according to Revelation, the last book of the Bible, there are many more plagues God will send in the future).
But I do agree with you in that we certainly bring all manner of misfortune on ourselves because of our wrongdoing, regardless of whether the wrongdoing is called “sin,” or “wrong action,” or stupidity, greed, or whatever. Even atheists would agree with you on this.