Bhagavad Gita Verse 21, Chapter 13

purushaha prakritistho hi bhungkte prakritijaangunaan |
kaaranam gunasangosya sadasadyonijanmasu || 21 ||
 
Purusha, when seated in Prakriti, experiences the qualities born of Prakriti. Attachment to these qualities is the cause of his birth in good and evil wombs.
 
purushaha : Purusha
prakritisthaha : seated in Prakriti
hi : only
bhungkte : experiences
prakritijaan : born of Prakriti
gunaan : qualities
kaaranam : cause
gunasangaha : attachment to qualities
asya : his
sadasadyonihijanmasu : birth in good and evil wombs
 
Imagine that two young brothers and their grandmother are watching a boxing match on TV. One brother is a huge fan of boxer A, and the other brother of boxer B. The two brothers get so involved in the match that they feel they themselves are in the boxing ring. The brothers start throwing punches in the air, mimicking the actions of the boxers. Also, when boxer A punches boxer B, the first brother feels exhilaration whereas the second brother feels pain. All this time, their grandmother is watching the match without any of these reactions.
 
This involvement with the boxers doesn’t end with the match. Boxer A always likes to wear a headband, so the first brother starts to wear headbands in the house. Boxer B always snaps his fingers at the end of every sentence, so the second brother begins to do that as well, much to the annoyance of his parents. Both the brothers have become so infatuated with their boxers that they take on their likes and dislikes. We may think that such behaviour only happens with children and teenagers, but something similar has happened to all of us, causing us to get trapped in samsaara.
 
We are stuck twice in samsaaraa. First, Shri Krishna says that the eternal essence has mistakenly identified itself with one body due to avidyaa or ignorance, just like the brother identified himself with boxer A. Instead of watching the IMAX movie of the universe like the grandmother, we get stuck to one character in that movie. When the eternal essence as though gets deluded with ignorance, it becomes the Purusha, and becomes “seated in Prakriti”. It forgets it real nature as infinite, indivisible and blissful. It assumes the properties of our body and thinks itself to be finite, divisible and sorrowful.
 
Second, having identified with a finite body, having taken the "upaadhi" or conditioning of a body, we get attached to the play of Prakriti, the play of the three gunaas or qualities. We get so attached to the forms of Prakriti that we generate selfish desires in order to repeatedly contact these forms, which are nothing but objects and people. Seeking a shinier car is a mistaken attempt to find joy in the car instead of understanding our true nature as joy itself. We become the brother who starts wearing a headband to feel happy, just because boxer A does so, when the brother was happy even before he know what boxing was.
 
So then, how do we get out of this two step problem of samsaara which causes us to “take birth in good and evil wombs”? We solve step one - attachment to gunaas - through vairaagya or dispassion, we learn to slowly wean ourselves off the influence of the three gunaas. We then solve step two - ignorance of our true nature - through jnyaana or knowlege, when we learn of our real nature as the eternal essence and internalize it through meditation.
 
An illustration of Purusha getting entangled in Prakriti is taken up next.