Bhagavad Gita Verse 17, Chapter 4

karmeno hyaapi boddhavyam boddhavyam cha vikarmanaha |
akarmanashcha boddhavyam gahano karmano gatihi || 17 ||
 
(The meaning of) Action should be known, forbidden action should be known, and also inaction should be known, for inexplicable is the course (nature) of action.
 
karmanaha : action
hi : for
api : also
boddhavyam : should be known
cha : and
vikarmanaha: forbidden action
akarmanaha : inaction
cha : and
gahanaa : inexplicable
karmanah : action
gatihi : course
 
Shri Krishna is going deeper into the definition of karma in this shloka. Previously, we examined the meaning of karma as selfish actions, and akarma as unselfish actions. Now let's look at what is meant by vikarma. Vikarma or forbidden action refers to any action that is not prescribed in one's svadharma. We need to use our intellect to determine what is vikarma based on our individual situation.
 
For example, one could be a vaishya (businessman). His duty is to conduct business and use the earnings for benefit of family and for the benefit society as a whole. There is absolutely no harm if he wants to earn more and more wealth. It is absolutely ok as long as he is using it for the benefit of family and society.
 
But if one is a student, his goal should be to diligently acquire knowledge. If his attention is diverted towards acquiring more girlfriends, that becomes vikarma. The key point here is that no outside entity can tell someone what their svadharma is. It has to come from within, from deep self examination and analysis.
 
Having examined the definitions of karma, akarma and vikarma, let us know go one step further and understand karma at a much deeper level. Shri Krishna gently warns us that we need to put forth effort to have a correct understanding of this topic, because it is hard to comprehend. Karma is a reaction produced by nature in response to our relationship to it.
 
Firstly, let us understand what is mean by our relationship to nature. It goes back to our thoughts and our motives. If we are motivated by a selfish spirit, nature will give us a negative reaction, just like electricity gives us a shock if we handle it improperly. Conversely, if we are motivated by a spirit of cooperation and selflessness, we will not get that negative reaction from nature.
 
Why so? Because we have seen earlier that the spirit of yajna is embedded in nature itself. Prakriti or nature is moving with the yajna spirit, and we are part of nature itself. So therefore, if our thoughts and feelings - not just our actions - are "in tune" with nature and the spirit of yajna, we will not accumulate negative reactions or karma.
 
Next, let us understand where these reactions come from. They do not come from some outside agency that constantly monitors our actions and gives us karma "points". These reactions come from nature itself. Nature is like a mirror - if you smile at it, it smiles right back. We have all heard the saying "what goes around comes around". That is karma.
 
So what does it mean for us from a practical perspective? We have to constantly use our viveka or discrimination to ensure our thoughts and feelings are working in the spirit of yajna. If our thoughts are unselfish, so too will our actions be unselfish. Otherwise, we will go on accumulating karma which gets lodged in our personality as vaasanaa, which is the very thing that stands between us and self-realization.