Vivekachudamani 357

समाहिता ये प्रविलाप्य बाह्यं
श्रोत्रादि चेतः स्वमहं चिदात्मनि ।
त एव मुक्ता भवपाशबन्धैः
नान्ये तु पारोक्ष्यकथाभिधायिनः ॥ ३५६ ॥

samahita ye pravilapya bahyam 

srotradi cetah svamaham cidatmani | 

ta eva mukta bhavapasabandhaih 

nanye tu paroksyakathabhidhayinah || 

(Sankaracarya's Vivekachudamani 357) 

They alone are free from the bonds of becoming who, having attained one-pointed absorption (samadhi), merge the objective world, the sense-organs, the mind, nay, the very ego, in the Self as pure Consciousness; and not those who merely blabber about their indirect Knowledge. 

The real purpose of yoga is to control the senses. Our material activities mean to engage the sense in some particular objective or enjoyment. That is our material engagement. And yoga system means that you have to control the senses and detach the senses from material enjoyment, or material pleasure and pains, and divert it, focusing towards seeing the Supersoul Visnu within your soul (self?). That is the real purpose of yoga. Yoga does not mean... Of course, in the beginning, there are different rules and regulations, sitting posture, just to bring the mind under control. But they do not end themselves. The end is to stop material engagement and begin the spiritual engagement.