prashaantamanasam hyonam yoginam sukhamuttamama |
upaiti shaantarajasam brahmabhootamakalmasham || 27 ||

Supreme joy certainly obtains this yogi with serene mind, whose passion has been quietened, who has become the eternal essence, and who is without sin.
prashaanta : serene
manasam : mind
hi : certainly
enam : this
yoginam : yogi
sukham : joy
uttamam : supreme
upaiti : obtains
shaanta : quietened
rajasam : passion
brahmabhootam : become the eternal essence
akalmasham : without sin
In one of the most classic shlokas of this chapter, Shri Krishna does something which is next to impossible – he puts the result of meditation into words that we can understand. He says that supreme joy comes to the meditator whose mind is quiet and free from sin, who has calmed his passions and who has identified with the eternal essence.
What is our situation in life for the most part? We constantly run after sukham or joy. If there is any chance of happiness that is within reach, we run after it. Unfortunately, whenever we run after joy, joy tends to run away from us. It is hard to catch. In the rare instance that we possess joy, we beg it to stay. We do not ever want it to leave us. This is also easier said than done.
Shri Krishna says that in the case of the meditator, it is joy that runs after him. It comes to the meditator and asks him “shall I stay with you?”. The meditator becomes what is sought after, joy becomes the seeker. Moreover, it is not ordinary joy that comes after the meditator. It is the most supreme joy. This is the difference between a bhogi and a yogi. A bhogi runs after joy, but joy runs after a yogi.
Now, how is the mind of such a yogi? It is extremely quiet, like a calm lake. He is able to view any kind of situation that impacts him with such dispassion that it is like watching the situation happen to an unrelated person. If it is a disturbing situation, lets say he suffers an accident, he smiles just like we smile at a character in a movie. There are absolutely no complaints for any situation from a yogi.
Next, Shri Krishna says that the yogi is “shaanta rajasam”, he has silenced the quality of passion within him. Rajas, the mode of nature that causes us to go outside ourself, is present in visible as well as in subtle form inside us. Through karmayoga, we can check the visible forms of rajas to a large extent. But it is only through meditation that we can completely remove the invisible, subtle traces of rajas within us. Till all the rajas is silenced, we should let it express in the form of performance of our duties, not any other actions.
Furthermore, the mind of the meditator is pervaded with a single thought “I am the eternal essence”. This is indicated by the word “brahmabhootam” in this shloka. When the meditator has identified himself with brahman, and removed his identification with everything else, then he automatically becomes one with the eternal essence. The removal of everything else in the form of impurities is indicated by the word “akalmasham”.
Shri Krishna concludes this topic in the next shloka.