"The human body is an energy system... which is never a complete structure; never static; is in perpetual inner self construction and self destruction; we destroy in order to make it new..."- Norman O Brown, Love's Body
The word ENERGY evokes images of power lines and outlets, or your metabolism, or a person running and being all hyper. However, the energy around us flows through an invisible web that connects us all to each other. A witch needs to become sensitive to that flow of energy; connecting through the channels and let it flow through you is the only sure way that your magic will work effectively. Even though we - as living things - are filled with energy (personal energy), we must also use the energy around us so that our own personal stach does not weaken and thus bring the body to an unhealthy state.
There are many forms of energy, being the one which is visible to us the most common (like a rainbow in the sky after a rainy day, or the light that the moon brushes out). As I've stated before, personal energy is the energy that we have in our bodies, the one that makes us go round and round. Metabolism, nerve impulses, body heat, all those count as personal energy. In order for the body to stay healthy, this energy has to be in perfect balance within.
The Earth energies are the ones we connect to when we are in ritual. It is the energy of the planet, the one that gives birth to all living things. It has been called mana or shakti kundalini. Avobe the Earth is the energy of the sky, the energy of the Sun and stars. Then we have the divine energy. This kind of energy is the one that does not belong to the polarity of Earth and Sky. It's pure divine energy, what we call unconditional love, used to create sacred spaces and rituals. The energy that is all loving, all knowing, beyond all good and evil.
During ritual, the things we use during our encounter with the God/Goddess is a symbol of an energy that exists on another plane. How well we understand the representation of such symbols and the energy that they carry is how efficient our magic can be. In order to bring through this divine energy, a circuit of communication must be set up in the form of visualization, symbols, ritual, and meditation. To keep the energy from dissipating, we use the magic circle.
Conway, D.J. Magick of the Gods and Goddesses: Invoking the Power of the Ancient Gods.
Cuhulain, Kerr. Full Contact Magick: A Book of Shadows for the Wiccan Warrior.
Penczack, Christopher. The Inner Temple of Witchcraft: Magick, Meditation, and Psychic Development.