"The miracle does nothing. All it does is to UNdo. And thus it cancels out the interference to what HAS BEEN done . It does not add, but merely takes away. And what it takes away is long since gone, but, being kept in memory, APPEARS to have immediate effects."

What has "been done" is God's will, creation, perfection, the establishing of you as an immortal being, perfect health, eternal life, happiness etc.

But what has been IMAGINED is the ego stuff which has tried to "interfere" with creation. This has produced denial and sickness and pain and suffering and death.

So what the miracle DOES, is that it UNDOES the INTERFERENCES, the ego stuff, so that all that REMAINS is the true-nature of the immortal spiritual self.

Some people interpret this to mean literally "miracles don't do anything". This is a gross error. They actually DO ACT to "cancel" or "reverse" or "dissolve" or "heal" the "strange distortions that were manifest" and wipe them away to RE-ESTABLISH the perfection and health that has been hidden by the ego's interference.

So the miracle actually UNDOES EGO, and therefore UNCOVERS perfection, by REMOVING the manifestations, symptoms, and effects of ego.

Thus they DO produce what appears to be an IMMEDIATE EFFECT. The stuff which is "being kept in memory" is the entire ego thought system, which is dissolved and undone and shone past, to ERASE IT. This produces the "appearance" of transformation even on a physical level.

If we were ALREADY in a state, in time, of perfection, miracles indeed would not DO anything. There would be nothing TO UNDO. But because we HAVE added layer upon layer of ego denial and suffering, THOSE things ARE UNDONE by the miracle, in an ACTIVE way.

When Jesus speaks of 'sickness' in ACIM, he doesn't just refer to what we think of as sickness.

You see, to Him, sickness occurs because of some very very fundamental things happening. e.g. "seeking outside yourself" produces sickness". e.g. "confusing the levels" (of consciousness) produces sickness. e.g. believing that causes are outside of you or that the body has its own will, produces sickness.

So really, when there is ANY seeking outside yourself, ANY reversal of cause and effect, ANY level confusion whatsoever, whatever results from that is given the label "sickness".

Sickness includes all physical sicknesses, diseases and death. But it also includes all mental illness, all fear, all upset emotions, all projections, all false beliefs, or mistaken sense of identity, all unawareness or unconsciousness, all behaviors inspired by the separate ego mind, etc... absolutely every activity or attitude of the separated self is sickness. Even the existence of the body itself is fundamentally a form of sickness, because the ego made it to enforce separation. Believing that you are not one with other people is sickness. Any form of separation is sickness.

So when Jesus refers to sickness in ACIM, he's referring to AAAAAAALLL of the forms and facets of 'a sick mind' in all the ways it manifests or distorts on every level in every way. Similarly, all of this entire motherload of 'states of being' that are not pure and holy, are sickness. And sickness also = fear, because "healing is essentially the release from fear". So sickness and fear are the same thing, and all distortions in the mind, and all ego in any way shape or form is sickness.

So when Jesus says you can perform miracles to 'heal the sick and raise the dead', he also really does mean the correction or undoing of the entire ego thought system, the entire ego 'world' of manifested interferences and distortions and unholiness.