What about situations where you have no other choice, and you know inaction would also be wrong, e.g. situations where you must choose what you feel to be the lesser wrong? Is that inevitably a sin?
Is there a hierarchy of sin to hep one decide in such difficult situations?
It seems that normative moral & ethical theories, whether consequentialist, duty based, rights based, or even virtue based, all seem to run into the problem of situations where the theory conflicts with our inner moral compass, our personal sense of fairness & justice, of right and wrong...
I'm curious to know if Christian moral philosophy has anything to say about that, as the Bible has examples of people commanded by God, or His representative(s) to act in conflict with their own personal sense of justice; but in those situations it (presumably) isn't a sin.
This suggests two possibilities, either your statement about what constitutes a sin is mistaken, or what you mean by 'When you know something is wrong' is really 'When you know something is contrary to God's command' (the tenets of Christian morality) regardless of your personal moral compass. Or perhaps there's some other possibility?