These various forms appear different in shape and size, yet they are of a single essence.... The Sixth Patriarch called it 'essence of Mind'... Here the Third Patriarch calls it 'timeless Self-essence.' Bankei called it 'unborn Buddha-mind.' They all refer to the same thing Buddha-nature, true self. This essence is not born and can never die. It exists eternally. Some call it energy others call it spirit. But what is it No one knows. Any concept we have of what it is can only be an analogy....