shareeravaangmanobhiryatkarma praarabhate naraha |
nyaayyam vaa vipareetam vaa panchaite tasya hetavaha || 15 ||

Whatever action is begun by a person, with the body, speech and mind, either per scripture or the opposite, these five are its causes.
shareeravaangmanobhihi : with body, speech and mind
yat : whatever
karma : action
praarabhate : begun
naraha : person
nyaayyam : per scripture
vaa : either
vipareetam : opposite
vaa : or
pancha : five
ete : these
tasya : its
hetavaha : causes
Let us quickly recap the concepts from the previous shloka. Any action that we perform has five components behind it. The body provides the foundation for the action. The instruments comprise the five organs of sense and the five organs of action. The energy system of the body, the praana, provides the fuel needed to perform the action. The individual notion, the ego, provides the motive behind the action. The daivam, Ishvara, ensures that the universe supports the performance of the action.
To drive home this point, Shri Krishna adds that there is no action that is beyond the realm of these five factors. In other words, the five factors are the material cause as well as the efficient cause or intelligence behind an action. Since a robot can perform any task that it is programmed with, it is easy to understand that the five factors are the material cause of the action. But when we say that they are also the intelligence behind the action, it is a little difficult to swallow. Our true self, the eternal essence, has nothing whatsoever to do with the action. The mind generates thoughts and the body performs actions.
Now, another point is taken up in the shloka. It is the very same five factors that can perform an action in conformance with the universe and its laws, as well as action that goes against the universe and its laws, also termed as a sinful action. The way a person looks at the world, as well as the nature of his intelligence, determines whether he will perform an action lawfully or sinfully. The entire process of action is analyzed in detail later in the chapter. This overview of the factors behind an action is concluded here, setting us up for the most important teaching of the Gita, taken up next.