Chapter VI Sloka 15

yuÃÚev< sdaTman< yaegI inytmans>,
zaiNt< invaR[prma< mTs<SwamixgCDit.

yuñjannevaÕ sad˜tm˜naÕ 
yogee niyatam˜nasa× |
þ˜ntiÕ nirv˜õaparam˜Õ 
matsaÕsth˜madhigacchati ( 6|15)||

Thus always keeping the mind balanced, the Yogi, with the mind controlled, attains to the peace abiding in Me, which culminates in liberation.
Commentary: Thus: in the manner prescribed in the previous verse.
The Supreme Self is an embodiment of peace, It is an ocean of peace. When one attains to the supreme peace of the Eternal, by controlling the modifications of the mind and keeping it always balanced, he attains to liberation or perfection.