In the context of spirituality human energy system is widely understood as chakra system within the human body. Yoga, specifically Samkhya Yoga, teaches us about the creation of the universe and its elements and tells us about the one, infinite, eternal source of all energy or life called Purusha, Consciousness or Brahman. It is the field of Unity, state of the enlightenment, root of all manifestation and the resource for the maintenance of all that exists. The creative principle within the Universe is known as Prakriti or Nature. The Yoga teaches us that Purusha and Prakriti or Shiva and Shakti are just two faces of one reality, that one does not exist without the other and that the manifested universe – every aspect of material creation - is the same with its source at every point of time and space.
The equating factor of everything that exists and can be experienced and cognized is the energy. The life and the universe that we know is nothing but the field of energy. We do not know from where this energy comes or what is the origin of it, but we know that the energy must have a source and we know that it cannot be destroyed. This eternal energy is known as Prana in Vedic philosophy while its transformations are known as different vibrations or frequencies that create five basic elements in the nature and all forms in it, as well as in the human body (terms are explained in separate articles on Prana, Akasha and Elements that will serve you as a guideline in understanding the human energy system).
The Shrishti Karana, part of the Vedic wisdom that deals with the beginning of the creation and its nature tells us that the primal manifestation of energy, or the first material manifestations from the one universal source are – Light and Sound.
Light is the first definition of manifested universe and it lies in the basis of the creation. Sound that was created in the motion of the Consciousness field and that emerged from the intention to expand consciousness is the sound Aum. Aum or the pranava is the embodiment of the Universal Consciousness and it represents awareness that spreads (this resembles the Biblical teaching about the beginning that is defined with the Word of God; also - Lord Jesus tells us that he is the Alfa and Omega – letters that symbolizes beginning and the end).
Here we come to the teaching about chakra system within the body. There are seven main energy centres in our body and these centres represent sources of energy for us. These sources are coded with a specific frequency of light – color and specific root sounds or seed mantra. We can describe these centres as gates through which we interact with the rest of the creation or universal energetic field.