There is a common misconception of karma in the Western world, a source of noise so loud it basically drowns out the signal. Karma is equated with vipāka (result), or the Christian concept of Galatians 6:7:
- "Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap. For he that soweth to his flesh shall of the flesh reap corruption; but he that soweth to the Spirit shall of the Spirit reap life everlasting."
In other words, what goes around comes around. Ironically, this inaccuracy is often thought of as a revolutionary, Eastern concept, with bumper-sticker rebellions like "My karma ran over your dogma." There is no concept in Buddhism that some ethereal force will make sure good actions will be rewarded; quite the opposite, in fact, as the First Noble Truth is, in one sense, recognizing that life is not fair. While Hinduism does have a spiritual force involved in karma, translating "karma" this way is inaccurate in both religions.
In reality, karma is Sanskrit for "action". That's right: karma means action. Action is its own reward.
Buddhist karma lies entirely inside the mind. When you perform good karma, your mind will build up positive memories and patterns that will make it easier to do it again. When you make bad karma, though, you will fall into a bad habit. Collectively, your bad habits are saṃsāra, the Buddhist cycle of birth and death, whence arises your suffering. Even good habits are often samsara because they keep you within the cycle. Truly good karma is liberating.