The Law of Karma

In Buddhist teaching, the law of karma, says only this: `for every event that occurs, there will follow another event whose existence was caused by the first, and this second event will be pleasant or unpleasant according as its cause was skillful or unskillful.' A skillful event is one that is not accompanied by craving, resistance or delusions; an unskillful event is one that is accompanied by any one of those things. (Events are not skillful in themselves, but are so called only in virtue of the mental events that occur with them.)
Therefore, the law of Karma teaches that responsibility for unskillful actions is born by the person who commits them.

Let's take an example of a sequence of events. An unpleasant sensation occurs. A thought arises that the source of the unpleasantness was a person. (This thought is a delusion; any decisions based upon it will therefore be unskillful.) A thought arises that some past sensations of unpleasantness issued from this same person. (This thought is a further delusion.) This is followed by a willful decision to speak words that will produce an unpleasant sensation in that which is perceived as a person. (This decision is an act of hostility. Of all the events described so far, only this is called a karma.) Words are carefully chosen in the hopes that when heard they will cause pain. The words are pronounced aloud. (This is the execution of the decision to be hostile. It may also be classed as a kind of karma, although technically it is an after-karma.) There is a visual sensation of a furrowed brow and downturned mouth. The thought arises that the other person's face is frowning. The thought arises that the other person's feelings were hurt. There is a fleeting joyful feeling of success in knowing that one has scored a damaging verbal blow. Eventually (perhaps much later) there is an unpleasant sensation of regret, perhaps taking the form of a sensation of fear that the perceived enemy may retaliate, or perhaps taking the form of remorse on having acted impetuously, like an immature child, and hping that no one will remember this childish action. (This regret or fear is the unpleasant ripening of the karma, the unskillful decision to inflict pain through words.)