The state of severance of union with sorrow is known by the name of yoga.

In Karma-yoga no effort is ever lost, and there is no harm. Even a little practice of this discipline protects one from great fear [of birth and death].

Yoga is difficult for the one whose mind is not subdued.

Karma-yoga is a supreme secret indeed.

This yoga should be practiced with firm determination and perseverance, without any mental reservation or doubts.

This yoga is not possible, for the one who eats too much, or who does not eat at all; who sleeps too much, or who keeps awake.