Law of Karma

Karma - action and reaction:
Vikarma - action with bad or binding reaction:
Akarma - action without reaction:

Karma does not necessarily mean past actions. It embraces both past and present deeds. Hence in one sense, we are the result of what we were; we will be the result of what we are. In another sense, it should be added, we are not totally the result of what we were; we will not absolutely be the result of what we are. The present is no doubt the offspring of the past and is the present of the future, but the present is not always a true index of either the past or the future; so complex is the working of Karma.

It is this doctrine of Karma that the mother teaches her child when she says "Be good and you will be happy and we will love you; but if you are bad, you will be unhappy and we will not love you." In short, Karma is the law of cause and effect in the ethical realm.

WHAT IS THE CAUSE OF KARMA?
Ignorance.

http://www.buddhanet.net/t_karma.htm