Yoga Sutras of Patanjali
1:2 Yoga is the cessation of the fluctuations of the mind
Everything we do in yoga should be seen as a tool for freedom from nonessential thought. The physical benefits are side effects. Doing yoga for the physical side effects is akin to taking cold medicine to get high. It does the job, but it was not the original intent of the product. If an addiction is developed towards the side effects, it changes the nature of the product. The yoga starts to build the ego and attachment to the body which is the opposite of freedom.
If you do a yoga that does not change the patterns of energy within you, I would say, don’t waste your time on it-Sadhguru
Modern Day Application
When you practice, your ultimate goal should be to quiet the mind. Without that quality, it is just stretching and exercise. It is not yoga. Don’t get me wrong, stretching and exercise are great things and can bring tremendous benefit to the body and many people go to class just for this and it is okay. Yoga asanas are therapeutic and healing and this is not to be belittled. You are not a bad person because you just practice for the physical benefits. You are actually a very smart person because the asanas are awesome. However, if we are going by Patanjali, who essentially took the most essential parts of the oral yoga tradition and wrote it down so us mere mortals could understand it, it is not yoga.
Why Is It Important?
When the mind is quiet, we experience true peace and freedom. It is not the events but our reactions to the events that happen to us that determine our happiness. When we learn how to bring peace and freedom to the mind, our lives are also peaceful and free. Another way to say it is, that it is not the poses that bring us freedom, it is our reaction to the poses that show us who we are and give us pointers to the path of freedom.