Bhagavad Gita Verse 32, Chapter 4

evam bahuvidhaa yajnyaa vitato brahmano mukhe |
karmajaan viddhi taan sarvaanevam jnyaatvaa vimokshyase || 32 ||
 
In this manner, various types of sacrifices have been explained in the Vedas. Understand that all those are born of action; having known this, you will be liberated.
 
evam : in this manner
bahuvidhaa : various types
yajnyaa : sacrifice
vitataaha : have been explained
brahmanaaha : Vedas
mukhe : mouth
karmajaan : born of action
viddhi : understand
taan : those
sarvaan : all
evam : in this manner
jnyaatvaa : having known this
vimokshyase : you will be liberated
 
With this shloka, Shri Krishna concludes the section on practical yajnyas. In this section, we came across many varieties of yajnya. There are several more types of yajnyas in the scriptures such as pilgrimages, how to perform poojas during certain festivals, chanting of japas and so on. With the guidance of a teacher, we can choose the one that works best for us and follow it diligently.
 
Having concluded this section, Shri Krishna now makes a very important point. He says that while performing these yajnyas, we should never forget that any yajnya is ultimately an action. We saw earlier that actions are performed by the gunaas of prakriti. And anything that is related to gunaas is distinct from the eternal essence. So, how can yajynas move us closer to liberation if they are in the realm of gunaas?
 
Another way of looking at this issue is as follows. Anything that is a result of action will always be finite by definition. We are looking for realization of the eternal essence which is infinite. How will yajnyaas, born out of finite action, make us obtain the infinite eternal essence?
 
The key point to understand here is that action does not yield realization, only knowledge can do so. Performance of yajnya is a preparatory step towards realization, just like we prepare for sleep in the night. We can lie down on the bed, we can drink a cup of hot milk, we can turn off the light and so on. But the onset of sleep happens on its own. Similarly, even if we perform yajnyaas, realization will happen when we gain the knowledge when we are not the doer or enjoyer of any actions.