"It is much easier for people to give up certain excesses and to perform mechanically a pranayama than to restrain a single habit which is a stumbling block on the path of spiritual progress. But, as it is said, everything mechanical concerns only the outer man and cannot reorganize the inner man, and therefore is worthless; for the transformation of the inner man is the only aim of all true Teachings. Therefore, one must clearly remember that all the Great Teachers care for and deal only with the inner man, whose sphere lies in the realm of thought. Thus, not a single high Raja Yogi or Agni Yogi needs any mechanical or physical exercises. The only concentration allowed by them is concentration on the chosen High Ideal, performed with an unfailing and continual determination to reach it..."