I found the Lord’s use of the word “sin” to be very interesting. I am sure a more detailed explanation follows later in the Gita, but for the purposes of the argument here, Sin is defined as not doing ones Dharma (duty, responsibility). I think this is a unique definition that seems to serve us well.
Most other religions or philosophies have lists of things that you shall not do. There seem to be such moral absolutes like gluttony, pride, adultery, lying, robbery, not worshiping 5 times a day etc. This has always seemed as a very rigid system to me. Because of this definition, we are constantly commiting sins. For example, we all seem to use what we call “white lies” to smoothen our daily interactions and tactfully deal with people. In such cases it even seems appropriate and “the right thing to do”.
This aspect of being constant sinners has never sat well with me. Its like telling a kid in school that he is always doing something wrong: we only get negative feedback. But worse is the fact that its absolute, with no flexibility to the current situation. Arjuna also succumbs to this misconception and hence he thinks that fighting against his relatives, teachers and friends will be commiting the worst sin possible. Thats because he thinks fratricide is moral absolute sin.
Thats why I think its great that the Lord defines sin as not doing ones duty. There are no moral absolutes. Everything depends on what your duty is at that time and place. If your relatives or your kin are doing bad things and it is your duty to protect people, then the execution of your duty is the right thing to do and hence is not sin.
One can argue that all this does is moves the concept of sin one level up from action to duty and that instead of figuring out whether our action is wrong, we have to figure out what our duty is and thats the same thing. I think this is a critical difference which we shall see in the succeeding stanzas and chapters. Infact Chapter 3 is on Karma Yoga: the Yoga of Action which teaches us how to perform any action.
Going back to the lack of moral absolutes, can it be really true that there is nothing that is completely wrong or completely right? How about actions like rape and child molestation? Can such things be the “right thing” in any conceivable situation? Or do we still have moral absolutes where these action cannot ever be someones duty and hence will always be sin?