Breathing is one internal function that the conscious mind can control with comparative ease. The effect of controlled breathing is almost like communication with all conscious parts of one's being saying to them, "Simmer down and listen; there is something beyond the turmoil". It is communication in action that often works when words merely go in one ear and out the other, not even changing the cognitive mind. In essence, the effect is to turn all the elements of our will toward stillness and waiting.
Educate your inner being in all aspects of life. Keep to the order you learned during your schooling. You did not begin all of a sudden to grasp the higher subjects; you started by learning the alphabet. The same applies to your soul. It is not good for it to strive toward exalted feats until it becomes familiar with the spiritual alphabet: humility and obedience. Let the whole of your life become a continuous prayer.