The word Karma means action. Everything we do is an action, as is every thought we have. Inherent in these, is the danger of believing that these thoughts and actions are who we are.
This is quite simple in theory. For example, we each have certain skills and jobs we do. As someone who has studied music since I was a kid, it’s easy for me believe that I am a musician. As yogis, if we believe that the essence of who we are is pure and unchanging consciousness, than anything else we identify with is just a product of the ego.
This is not to say that we don’t each have certain skills and traits. These traits are the results of past karma, which make us head in one direction and not another. (As someone who has always been drawn to music, you really don’t want to see my try to engineer the next fancy skyscraper!) Past thoughts and actions build upon each other, lending us able to do some things more easily than others which is all good until the ego jumps in. The ego lives in a world of wins and losses. If something strengthens what the ego believes to be the self, it is a win, but if it conflicts it is a loss.
This continues when we deem some tasks to be below us, some positions out of reach, some interactions pleasant, some people frustrating, etc. It is true that we can find a great relationship, be given a promotion we don't feel ready for, be full of road rage in heavy traffic, but through all of these scenarios, the actual essence of who we are will not have changed at all. If these actually changed us, that promotion we've always dreamed of would finally make us happy!
This is where Karma Yoga comes in.
Karma Yoga is a way of purifying the mind. It is not just something we do on a yoga mat, seated in meditation, in fancy yoga clothes, but something we can do all the time. It is using each thought and action to take us closer to our true identity of unlimited consciousness, and away from what the ego has attached to and identified with. By doing Karma Yoga we strive to remove the ignorance of identifying with our likes, dislikes, relationships, jobs and skills as inherent in the self. In essence, practicing Karma Yoga removes the association we have with this false sense of "I am."
The trick of Karma yoga is acting without attachment to the results. Remember that the ego works in wins or losses. It is either getting strengthened or being challenged. (And the ego is way unhappy when it’s challenged!) In Karma Yoga, we realize this, and work to move beyond these wins and losses by using the actions we make in our daily lives. We do our duties, which might mean taking care of our family or community, doing our job, not because it is who we are but because it can take us closer to realizing that we are not the actions themselves.
Karma Yoga is action, but it is skillful action. We all act and we all have thoughts, that will not change. But if we are seeking purity of mind, we do not want to reinforce what the ego desires. We will experience likes and dislikes, but through our actions, we should learn to see them for what they are and not who we are.
This is an essential first step not just for a yogi, but for everyone seeking clarity of mind. Otherwise all of our thoughts and actions will stay rooted in our perceived desired outcome which is what the ego falsely thinks will bring about happiness or contentment. (If that was going to work, it would have by now!) As a Karma yogi, we must do our work without associating with the outcome. Anything else is our ego taking us for a ride.