
A visitor asked Yogananda:
“What is YOGA?”
Paramahamsa Yogananda replied:
“Yoga is union.”
Etymologically, this word is similar to the English word “yoke”, which means “yoke”.
Yoga means the union of being with God or the transcendence of the limited, ephemeral IE and the immersion in the Supreme Divine Self, the Infinite Spirit.
Most Westerners and also many Indians confuse Yoga with Hatha Yoga – a branch of Yoga that is based on the yin-yang, ha-tha polar harmonization of the being by practicing certain body postures, called in Sanskrit ASANA.
Hatha-Yoga is a spiritual diciplina.
I have no intention of devaluing Yoga postures. Moreover, the body is part of human nature and must be maintained if we want it not to become, at some point, an obstacle to our spiritual forces. Sometimes, aspirants who seek to find God attach too little importance to Yoga postures. However, in order to attain Supreme Liberation, it is not mandatory for the being to practice asanas.
Hatha Yoga is the branch of Raja Yoga that deals with the physical body, Raja Yoga being one of the systems of Yoga science. Raja Yoga is a set of spiritual practices that help the human consciousness to connect to the Divine Consciousness.
Yoga is a science ,

in the sense that it provides practical methods of control over the body and the spirit, necessary to achieve the state of deep meditation.
It is an art, due to the fact that we will achieve mediocre results if we do not practice it with intuition and sensitivity.
Yoga is not a belief system. It takes into account the mutual influences of body and mind, seeking to harmonize them. In fact, often the mind is not able to concentrate due to tensions or diseases stored in the body, thus stopping the evolution of the being. Due to the fact that the mind is dissipated or paralyzed by negative emotions, the energy of the being is greatly diminished.
A large number of them are, what they call the Indians, some “great yogis”. They have risen consciousness from the state of attachment to the body to the state of identification of being with the Supreme Self. They discovered through the means of devotion, the secret of channeling the feelings of the heart to the Spirit, instead of letting them manifest as emotions Chaotic. They realized that the gate of the spiritual vision is located between the eyebrows – energy center through which the spirit immerses itself in the Cristic Consciousness. They discovered the secret of stopping breathing and the manner in which, in this state, the soul may ascend to the heights of the spirit. Her have discovered the state that some occultists call “marriage” mystical”, in which The Eternal Spirit of being immerses itself in God and becomes one with Him.

Mainly, Yoga acts on the energy of the body through techniques called PRANAYAMA (energy control; PRANA also means breath).
Yoga teaches us how, through breath control, to calm our mind and reach a high degree of consciousness. The most advanced levels of the Yoga system lead the being beyond the techniques and show the yogi or the Yoga practitioner how to direct his concentration in such a way that not only to harmonize his being with the Divine Consciousness, but also to immerse himself in this Infinite Consciousness with his whole being. Yoga is a very old science, thousands of years old. Its teachings the essence of the legendary grandeur of India.
The truths that are revealed by this system do not belong only to India or only to those who consistently practice yoga techniques. Many saints of other religions, including Christian saints, have discovered in their spiritual practice various practices that are even similar to yoga techniques.
Yoga completes the biblical texts, teaching the being how to love God with his heart, with his mind, with his soul, with all his strength.
The energy of the ordinary being is blocked on its lower levels. The lack of availability of this energy prevents the believer from loving God with all his might, with all three aspects of his nature: heart, mind, and soul. True inner communion is possible only when the being has managed to unlock the energy of the body and to sublimate it, through deep meditation.
- excerpt from the book “Conversations with Yogananda” by Swami Kriyananda