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.
Ignorance of spiritual laws is bondage; knowledge of spiritual laws is freedom; application of spiritual laws is wisdom.