Chapter VI Sloka 20

yÇaeprmte icÄ< inéÏ< yaegsevya, 
yÇ cEvaTmnaTman< pZyÚaTmin tu:yit.

yatroparamate cittaÕ 
niruddhaÕ yogasevay˜ |
yatra caiv˜tman˜tm˜naÕ 
paþyann˜tmani tuÿyati ( 6|20)||

When the mind, restrained by the practice of Yoga attains to quietude and when seeing the Self by the self, he is satisfied in his own Self, ......

Commentary:
The verses 20, 21, 22 and 23 must be taken together.
When the mind is completely withdrawn from the objects of the senses, supreme peace reigns within the heart. When the mind becomes quite steady by constant and protracted practice of concentration, the Yogi beholds the Supreme Self by the mind which is rendered pure and one-pointed, and attains to supreme satisfaction in the Self within.