Breathing is the connection between the mind and the body. When the mind concentrates on the breath, it focuses attention on the present moment. Breathing is the first step on the path to discover your spiritual nature. As you get the body to breathe correctly, the mind settles down, and that creates fertile ground to develop whatever spiritual nature exists within you.
People are like stained-glass windows. They sparkle and shine when the sun is out, but when the darkness sets in their true beauty is revealed only if there is light from within.