What is karma and how does it work?
Karma is the cosmic law of action and reaction. Under its control we souls in the material world reap good or bad results according to each act we perform.
Karmic reactions include not only things that happen to us, but such things as our health, wealth, intelligence, physical appearance, and social status, as well as our personalities and inclinations. While we have some freedom to choose our current acts, our choices are influenced by our natures, or personalities, which have developed from our previous actions. For example, good choices tend to make us good persons who make further good choices.
The law of karma begins to act upon us when we desire to enjoy separately from Krishna, and it locks us into an endless cycle. Each action begets a reaction that begets another action, and so on. Whether the reactions are good or bad, we must repeatedly accept new bodies in order for the reactions to play out. And each lifetime in a material body means unavoidable miseries, such as disease, old age, and death.
While the Vedas give directions for assuring good reactions, they tell us that the only truly beneficial course of action is to perform spiritual acts that can gain us freedom from the bonds of karma. Spiritual acts are acts for the service of Krishna and are the essence of Bhakti yoga. They awaken our innate love for Krishna, destroying our desire to enjoy separately from Him, which is the root of our karmic bondage.