Karma has been the subject of innumerable discussions and interpretations. Although of Hindu origin its basic notion of cause and effect seems attractive to many in the West as well.
As opposed to Western religious traditions which view Divine judgment as imposed upon the soul from outside of itself, karma is an impartial, nonjudgmental notion. The soul finds itself after death on a particular spiritual plane based upon its thoughts and actions of the previous lifetime.
In this sense karma is neutral. Less elevated choices result in a lower spiritual level after death. The options to evolve spiritually seem best obtained during physical incarnation at which time free will choices are at play.
Whether or not karma plays itself out within one individual lifetime or must await another is of some controversy. We tend to use the phrase what goes around comes around as if it does so within our individual lives.
There is no judgment as to which soul is "better" than another. Would we judge a kindergarten student on as inferior to a college student? Each exists within their level of achievement. Each is capable of upward or downward progression.
Another fascinating quote (uknown source) adds another perspective to the concept of karma– What you do to me is your karma, how I react is mine.
This notion challenges our usual response to any insult or challenge. Our usual default position is to become defensive and reactive. We may exchange negative responses or actions which ultimately bring us down to a lower spiritual plane.
An ancient Chinese saying states If you hate another person, you might just as well dig two graves.
We should remind ourselves that karma will answer many of our desires for revenge. Reconciliation will raise us up. But this is not the same as giving in or submitting to inequities or damaging actions. Self-defense is not spiritually demeaning. But it challenges us as to the degree of action against an aggressor.
So be mindful of our own actions and thoughts. We are ultimately responsible for their karmic consequences.