The Fifty Miracle Principles of A Course in Miracles
by Kenneth Wapnick
 

Principle 34

Miracles restore the mind to its fullness. By atoning for lack they establish perfect protection. 
The spirit's strength leaves no room for intrusions.

This should be understood as meaning that miracles restore to the mind the awareness of its fullness, because the fullness or the abundance of God has never left. All that the miracle does is take away the veil that the ego had put there that kept hidden from us the abundance of who we really are. By atoning for lack (i.e., by correcting for lack), miracles establish protection. The ego teaches us that we are lacking something, which means we are vulnerable. This means that we have to be protected. What the miracle does is show us that there is no lack in us, and therefore we do not need any protection. The protection of spirit, thus, is merely the awareness of the invulnerability of spirit. A child of God can never be hurt. That is one of the clearest understandings we could have of the meaning of the crucifixion. That is what Jesus taught us: despite what the world perceived, nothing was being done to him. His body may have been attacked, but he could not have been attacked. He identified with the perfect protection of spirit because he knew Who he was and, therefore, it did not matter what was done to his body, whether physically or psychologically. That is the perfect protection of spirit. At that point, then, spirit cannot be intruded upon. It is as if there is a circle of light around us that we identify with, and any darkness that the ego would try to throw up to us would just be dispelled by the light. You cannot introduce darkness into a room full of light. Darkness is the absence of light, which really means that darkness has no properties of its own. Identifying with the light of Christ, Who we are, is our protection. What is interesting is that sometimes people try to concretize that in some way by trying to extend or manifest a circle of light around them, or they will beam light or something like that. All that does is make the body real and make danger real. Therefore, all you need to do is know Who you are, and that knowledge and that awareness is the light. You do not have to do anything. Once you do something, that becomes a defense. You do not do anything; you just remember Who you are, and that being is beyond all doing.