This is a very subtle point, difficult to comprehend. The significance behind it is exceedingly hard to appreciate. This is because we have not been accustomed to think in this manner. We have been told by teachers, and the popular books on Yoga, the common-place routines which we have to pass through when we become religious or devoted or inclined towards Yoga. But then, inasmuch as true Yoga is an internal adjustment rather than an external practice, it requires greater effort on one's own part than in the usual routine affairs of life.
Yoga is more a state of being rather than outward doing.
Any amount of external doing may not be Yoga at all. Because one will be the same person inwardly with no difference whatsoever, if one's outlook of life has not changed. If the mind persists in thinking in the same old manner there would be no progress made. Honesty in one's own heart is essential. We should not be self-deceptive individuals.