The Law of Karma postulates that the whole cause produces an effect and that the whole effect has a cause.
Karma begins in thought and is reflected in another thought, words, and deeds. The Law of Karma covers everything we think, verbalize and do. When we wish harm to someone, consciously or unconsciously, even if we have not verbalized through an aggressive criticism or acted in the sense of that desire, we are producing karma and will have the consequence of these negative thoughts and desires through the negative situations we attract in our lives.
Therefore, the conscious and deliberate decision to observe our negative thoughts helps us to refrain from karma that would resonate in negative situations that we may go through in the future such as diseases and losses. The vigilance of our thoughts must be constant so that we do not transform our mind into an unconscious machine, producing future adversities.
The Law of Karma is parallel with Newton’s Third Law – the so-called Law of Action-Reaction – according to which, any body that exerts a force over another, receives a force of equal intensity, direction and opposite direction.
Karma, in Sanskrit, means action. Nevertheless, the concept of action when it comes to the Law of Karma also encompasses desires and words. Therefore, a human being cannot consider himself free to incur karma just because he has not come to realize an action since both desire and word already contain in themselves very powerful creative forces that will affect reality at the moment they manifest themselves.
This is exposed in the book Autobiography of a Yogue of Pahamahansa Yogananda when Mukunda (Yogananda) raises his hand with the intention of killing a mosquito that has just stinged him in a leg and stops for fear of producing karma before the severe gaze of the master who asks him why it does not finish what he started, explaining to him that the simple desire to kill the mosquito has already produced karma, the realization of this action is only the mere continuation of that same karma.
When a human being intends to harm someone, even if he has rethought his behavior and ended up giving up his negative action, it will already result in the negative karma of that negative desire although if it had materialized, karma would have been much more powerful.