Ego - Words used in A Course in Miracles

  Ego is a thought within the mind believing that it is separate (from … everything). This impossible delusion [the wave thinking it is separate from the ocean], becomes your identity.

                    

You can see yourself as separated from your meaning only by experiencing yourself as unreal. This is why the ego is insane; it teaches that you are not what you are. That is so contradictory it is clearly impossible. T-7.III.2:5-7. 

The ego is nothing more than a part of your belief about yourself. Your other life has continued without interruption, and has been and always will be totally unaffected by your attempts to dissociate it. T-4.VI.1:6,7. 

Nothing can reach spirit from the ego, and nothing can reach the ego from spirit. Spirit can neither strengthen the ego nor reduce the conflict within it. The ego is a contradiction. Your self and God's Self are in opposition. They are opposed in source, in direction and in outcome. They are fundamentally irreconcilable,because spirit cannot perceive and the ego cannot know. They are therefore not in communication and can never be in communication. T-4.I.2:6-12. 

The ego exerts maximal vigilance about what it permits into awareness, ... Sane judgment would inevitably judge against the ego, and must be obliterated by the ego in the interest of its self-preservation. T-4.VI.1:3,6.

Only your allegiance to it gives the ego any power over you. T-4.VI.1:1.