Bhagavad Gita Verse 28, Chapter 3

tattvavittu mahaabaaho gunakarmavibhaagayoh |
gunaa guneshu vartanta iti matvaa na sajjate || 28 ||
 
But he who knows the truth, O mighty-armed, about the divisions of gunaas as well as their functions, recognizes the interplay of gunaas (everywhere). Having known this, he does not get attached.
 
tattvavit : knower of truth
tu : but
mahaabaaho : O mighty-armed
gunaa : gunas
karma : functions
vibhaagayoh : distinction
gunaa : gunas
guneshu : in gunas
vartanta : act
iti : this
matvaa : having known
na : does not
sajjate : get attached
 
Previously, we learned about the ignorant individual who is deluded by the notion that he is the doer. But then, what does the wise person know that the ignorant one does not? Shri Krishna explains that point here.
 
The wise person is termed a "tattva-vit" - one who knows the truth - by Shri Krishna. The truth, as we saw earlier, is that all actions in this world are performed by prakiriti. And prakriti is comprised of the three gunaas and their respective functions, termed in this shloka as "guna-karma-vibhaaga". But how exactly do we know that prakriti causes the actions, not the "I"?
 
Our sense organs are like agents that send messages to the mind when they perceive an object. For instance, if you hold a rose in your hand, the eyes, skin and nose send different signals to the mind. The mind creates a holistic picture from all those signals - "this is a red rose" - and sends it to the intellect. The intellect analyzes that information and makes a decision - "buy this rose", having consulted its memory of past experiences with roses.
 
This means that perception, thinking, decision-making - all these functions are part of prakriti, operating based on laws set by prakriti. The "I" is the eternal essence, different from prakriti.
 
So therefore, if one knows that he is not the doer, and that things are happening of their own accord, he does not get attached to anything in this world. He becomes a witness or a "saakshi", just like someone watching a play does not get attached to one actor or another. Another example is the process of digestion. We are not attached to it because we know that we are not the doer in that instance. The notion that everything is an interplay of gunaas may seem abstract and theoretical. One can only gain a first-hand experience of this truth in deep stages of meditation.
 
This teaching is beneficial in our day-to-day lives as well. If we contemplate on this teaching, it has the effect of thinning our ego. Once that happens, it makes us very humble and reduces several negative emotions like fear, anger, stress and so on. Now, we may fear that this teaching makes us lackadaisical. On the contrary, it makes thinking clear and actions more efficient by getting rid of negative emotions that drain our mental energy.