"For sickness is the witness to his guilt, and death would prove his errors MUST be sins."
Here's the thing about why the body HAS to be healed.
It's simply a matter of cause and effect. The mind is the cause of the body. "The mind makes this decision as it makes every decision responsible for the condition of the body." The mind PROJECTS the body. At all times. Think of the body as like an image which is being projected by a movie projector. It's nothing but a 3D image. And it has no power to determine its own condition. It can only be what the projector projects it to look like.
So now imagine that your mind decides to attack your brother. By doing so, and in order to do so, it projects an image of a body which exhibits signs of attack, in one way or another. And thus the image itself now depicts the attack, by showing up as having damage, deformity, malfunction, sickness, symptoms, death etc. The body is used as a weapon to demonstrate the attack thought. And because the mind is ALWAYS the cause of the body, with the body as its effect, this IMAGE can only persist in the world so long as the mind is CAUSING it. There cannot be effects without causes.
The mind is responsible for the body showing up as sick or damaged. So long as the body therefore is showing up as sick or damaged, the mind that is projecting the body IS responsible for CAUSING it to show up as sick and damaged, which means the mind IS STILL USING IT FOR ATTACK. And so long as this image is being projected into the world of an attacked/attacking body, it PROVES... beyond all doubt.... that the mind HAS NOT BEEN HEALED. Because so long as there is an effect sitting there in a damaged state for everyone to witness, it proves THERE WAS A SIN. And it also proves the sin is still ONGOING.
The mind is having to constantly "hold" the body in a state of suffering in order to KEEP SHOWING a picture of crucifixion to your brother, which is how you attempt to accuse him of putting the effects into the body. Your body being sick shows him what HE DID TO YOU, because you can only have this attacking attitude when you perceive your brother is the CAUSE of you, which is what produces effects of sickness due to level confusion. So long as your body is sick in any way, YOUR MIND DEFINITELY IS STILL ATTACKING. And so long as the body remains in that sick state, it not only proves sin is real and attack has and is happening, it also proves the mind is not healed.
"A damaged body is PROOF the mind has not been healed."
There is NO ESCAPING THIS LAW. Your body is YOUR responsibility. If it is sick, you are making it sick. If it shows up as suffering, you are constantly maintaining the suffering. If it shows signs of damage, you are constantly putting the damage there, as the movie projector. If it seems attacked or has symptoms, YOU WANT THEM TO BE KEPT. This is all basic cause and effect. Your body as an effect of your mind CANNOT HAVE EFFECTS WITHOUT YOU CAUSING THEM. And so if the body IS still showing up as sick, YOU ARE CAUSING IT. Which means you are still attacking yourself and your brother!
You cannot simply think you have made a mess of the body and that the body now is in a state of sickness and it will just stay in that state of sickness "by itself". It does not stay sick or well by itself. It is just an image you project. YOU determine EVERYTHING ABOUT IT at all times. EVEN when it is dead. And so this means that so long as there is still evidence and PROOF in the dream, that sin has occurred or is occurring, CAUSING there to be effects of suffering in the body, THE SIN HAS NOT BEEN UNDONE.
This is a vital fact to realize. So long as the EFFECTS are remaining, THE SIN IS STILL HAPPENING. The causality is still happening.
And this means that quite literally, if you are going to have a mind that is healed and is free of sickness, YOU CANNOT keep maintaining sickness in the body. You cannot keep putting sickness into it, or projecting sickness, or showing sickness to anyone in any way. The ONLY way you can do so is to STILL BE SICK mentally. If there are effects, there is a cause. YOU are the cause. If the body does not "get healed" or rather, if the mind does not heal and thus CAUSE a projection of a body IMAGE which shows up as free from suffering, then your mind IS NOT healed.
So long as there is proof, evidence, demonstration, witness, testimony, or attesting of attack and sickness WITH AND IN AND THROUGH the body, YOUR MIND IS STILL ATTACKING YOUR BROTHER. The only way for you to stop attacking your brother, therefore, in this world, is to PROVE that you are no longer attacking by REMOVING THE EFFECTS, ceasing the demonstration of death, UNDOING the sickness, cancelling the symptoms, reversing the suffering and DEMONSTRATING a body which is completely free of sickness and pain. UNTIL YOU DO THAT, YOUR MIND IS NOT HEALED. Because if that body is STILL showing up with sickness, YOU DID NOT HEAL IT, because you do not WANT to heal it, because you are STILL attacking.
"Damaged bodies are accusers". They testify that your brother is a guilty fucker and has sinned against you. It is your PROOF of his sin. And you hold this proof in front of his eyes for all to see to PROVE that he HAS DONE THIS TO YOU, and to demonstrate his sinfulness and testify against him. You cannot be doing that if you are going to be a teacher of God, a healer, or an extender of love.
When the mind is truly healed, it will testify to its healing by expressing MIRACLES OF HEALING to the body which result in the body being projected AS HEALED, free of sickness and pain and suffering and damage of all kinds. PHYSICALLY. "A guiltless mind cannot suffer. The mind, BEING SANE, HEALS THE BODY." "A sick body makes no sense."
This is the teaching of A Course in Miracles. It is basic cause and effect. If the effects are still there, SO IS THE CAUSE. Until the effects are REMOVED, literally, the cause MUST still be happening. You do not merely make decisions at one moment in time and then keep the consequences. Decisions are CONSTANT BELIEFS. Until the belief is corrected and undone and ITS CONSEQUENCES ARE REMOVED BY THE HOLY SPIRIT THROUGH MIRACLES, the mind is not healed.
And that does literally mean that, if the body is sick, it PROVES the mind is sick. If the body is healed, IT PROVES the mind is healed. There is no exception to this. No escape from it. No loopholes. Mind causes the body. You are responsible for the state of your body as much as your state of mind. This is why "Only the mind and body need atonement."
The body IS a symbol in a dream, a teaching device, a device for communication, and what you use it for IT BECOMES. Use it for attack and it is attacked and shows up as sick. And it will STAY in that state as long as it is being USED for attack. And when the body is used to extend love and healing, the body will be HEALED, and it will show up as healed so long as it is used for healing. This is all in A Course in Miracles. This is not some magical fairytale bullshit that I made up myself.
This is also why you must "swear not to die". If you produce a dead body, it is because you have ATTACKED SEVERELY. And the body is PROVING that your mind is an attacker. If you do not attack, the body CANNOT BE SICK, NOR CAN IT DIE, because YOUR MIND IS CHOOSING that it only depict healing and health and harmlessness. This is why the body CANNOT DIE unless YOU CHOOSE to make it dead. And if you choose to make it dead, you are not doing God's will and are PROVING your mind is not healed.
"A dream of death is not left by death but by truth."
This is one of the more radical teachings in the course which is hotly defended against by many people. Not only the idea that you have to heal the body in order to demonstrate the Holy Spirit's purposes, but also that you MUST NOT MAKE DEATH HAPPEN otherwise you are failing the curriculum. No-one in his right mind would attack himself and his brother so severely as to SHOW a picture of total DEATH to another person in order to PROVE THEY ARE SINNERS. That is what dead does and is. It is a testifying that your brother is the cause of you and sinned and made you dead. Every death is an accusation of sin. YOU MUST NOT DIE. You must demonstrate only symbols of life and immortality.