a. Kamma as intention
Essentially, kamma is intention (cetana), and this word includes will, choice and decision, the mental impetus which leads to action. Intention is that which instigates and directs all human actions, both creative and destructive, and is therefore the essence of kamma, as is given in the Buddha's words, Cetanaham bhikkhave kammam vadami: Monks! Intention, I say, is kamma. Having willed, we create kamma, through body, speech and mind.[2]
At this point we might take some time to broaden our understanding of this word "intention." "Intention" in the context of Buddhism has a much subtler meaning than it has in common usage. In the English language, we tend to use the word when we want to provide a link between internal thought and its resultant external actions. For example, we might say, "I didn't intend to do it," "I didn't mean to say it" or "she did it intentionally.