God has one law. It is very simple.
God can only create in his own likeness. He doesn't know anything else. He creates beings - sons or souls - who are all identical to Him, and therefore are identical to each other. What applies to each one of them, applies to all of them equally. What is true of one, can be said to be exactly true of all of them.
This sets up "The Golden Rule", which is the primary law of God's creation, that everything applies the same to everyone, everywhere, at all times. The law simply states that what applies to you applies exactly the same to all brothers.
This law is always in effect. It is permanent. You cannot escape it. The law is in effect whether you like it or not. The law is in effect regardless of whether you are awake or asleep, aware of Heaven or suffering in the dream of spacetime. The law is the truth.
Our friend "the ego" is nothing other than the attempt to DENY that the law is in effect. It is an attempt to be outside of the law. The ego is nothing other than the belief that something DIFFERENT applies to one son versus another.
If the law of God means UNCONDITIONAL LOVE, since all sons are loved equally, then the ego means CONDITIONAL LOVE or "special favor", in which some sons are to be treated differently and unequally from others. Special love is a lack of love and so the ego is a thought system of lacking equality and unconditionality.
When you are trying to be "in the ego", you are in denial of the law. That doesn't mean the law stops applying. Denying that it always applies is suicidal. What happens when you try to operate outside of the law is that you will hurt yourself. You will believe that you can do something to others that you yourself escape the consequences of, and yet you will not escape those consequences.
When you do not treat your brother as a perfect identical equal, you will think you can get away with murder by getting away with attacking them and avoiding the effects. But you will not escape the effects. What you attempt to do to him you WILL do to yourself, because the law is always functioning. You cannot attack without being attacked. You cannot treat someone in a special way without withdrawing from love. You cannot attempt to hurt without hurting yourself.
The Golden Rule - the one law of God - also applies in the dream in terms of bodies, sickness, and death. The Course teaches clearly that if you show your brother a physical body which is sick, you are accusing him of sin and are attacking both of you. When you use the body for attack it becomes attacked and weak and sick and dead. This is a consequence of denying the law of God.
Simply, what applies to you always applies to others. So when you go into attack, attack is the idea that you can be different to others and have special treatment. This differences drives a wedge of separation between you and your brother and attempts to assert that what applies to them does not apply to you, or that you can attack without being attacked. This is the basis of all projection, where you try to project blame onto another as if to say "that is true of you, but not true of me".
When you do this, you are in denial of the law, and the law is still functioning, and so you will experience a split mind and are attacking yourself. You cannot cause your brother to be treated separately without treating yourself separately. Separation comes BETWEEN you. The body comes BETWEEN you as a separation device. You cannot have something apply only to him and not yourself.
Sick bodies are accusers. When you try to make your body sick you are accusing your brother of sin. That means that in your attempt to "make plans for him" you inevitably end up hurting yourself. You cannot accuse him of attack without being attacked. And so as you try to make out that your brother is a sinner, you are accusing yourself. It applies to you as it applies to him. And this hurts you. You will experience the consequences. It seems to be to an unfair consequence or something you did not want, but you literally did it to yourself. Whatever you try to do to another, you WILL do to yourself.
The Golden Rule also works in your FAVOR when you comply with it and recognize it and work WITH it. Recognizing it is the secret to salvation. That means you must be willing to have the truth be the same for everyone, all are treated equal and no-one is special. And that means moving into unconditional love. Here, the Golden Rule actually supports you and helps you, because it ensures that giving and receiving are one, therefore as you treat others with love you receive love. As you give miracles, you receive miracles.
When you acknowledge the law is in effect and you COMPLY with it, it ensures that you will be treated with unconditional love, that you will have access to sharing the entire treasure of God's creation, and that you will recognize your brother as your identical equal. "Healing is a thought in which two minds perceive their oneness and become glad". This means that the two minds recognize the law, know it to be true, see that they are identical children of God, and celebrate their equality.
A Course in Miracles is entirely based around this law. All of its concepts about how what you do to others you to do yourself, how giving and receiving are one, how you attack the body, how you become sick, how you must demonstrate a BODY THAT IS FREE FROM ATTACK, and how you must overcome death, is all based on the law of God - the Golden Rule. This is why Jesus says that either everything lives or everything is dead.
When the rule applies and you acknowledge equality, you are recognizing that anything God creates must be like him, and since He is life, everything He creates must live. And that means ALL that He creates is alive forever. And in this acknowledgement you are acknowledging that YOU are alive and cannot die, any more than anyone else can. Acknowledging life is the resurrection and in the resurrection the curriculum ends, because it's there, in the atonement, that you acknowledge and receive the unconditional love that comes from ALIGNING with the law of God. Accepting the truth.
When you comply with the law, everything is peaceful in Heaven. When you oppose the law, you make yourself suffer. Denying the law is ego and is suicide. Accepting the law is heavenly and protects you perfectly in eternal life.