"WHAT IS NOT LOVE IS MURDER" - ACIM
Here's how this works.
A mind which is fully awake and aware, recognizes that it actually shares a mind with everyone. It is at one with them. It sees its own identity within others, and knows that they are part of itself.
A mind of oneness therefore recognizes that whatever applies to others directly applies to itself. It is aware enough to see that, because it is "in" others, if it were to attack others, it would be attacking itself. And because this is very obvious to the awake mind, it recognizes that such actions would be completely self-defeating, and so does not attack.
When the mind can see clearly that it is one with others, it will treat others only with love, because to do anything else would hurt its own self.
However, when the mind enters into a belief in separation, what it's doing is it's introducing an illusion of denial inbetween itself and others. This denial makes it seem as if other people do not have "shared interests" with itself, other people are different somehow, other people are disconnected from itself, and therefore what applies to them does not apply to itself. It does not recognize or see itself in others so does not believe that what applies to them applies to itself.
On these terms, the mind is now partly unaware that it is one with other minds, does not see itself in others, and does not recognize that to hurt others would hurt itself. It now seems plausible that there is an `option`, a possibility, to do something unto others that is not done unto itself.
Another way to put this is that a separation is introduced in-between cause and effect. The mind now believes it is capable of causing effects in others which are not caused in itself. It does not see that attempting to hurt others hurts itself, so it think it can "get away with" or be excluded from those effects.
The idea of being able to do something to others which does not directly affect yourself, is the idea of "getting away with murder." It means you can now seem to attack another without experiencing the consequences. This is attempted murder. The entire ego thought system is based on this, and absolutely everything that happens in the ego thought system is murderous!
The problem of the mind then is that even though it believes it is not one with other minds, and that it can get away with attacking/causing without being affected, it's actually not true that it gets away with it. In one way or another, the mind IS still attacking itself, and it is hurting itself when it tries to hurt others. The ego will claim this is not true, and that you can escape from the consequences, but it is in denial. If the mind attacks another, it itself will be attacked BY itself.
This then becomes the ego trap of believing that you can get away with projecting your sin onto others without having to deal with the consequences. It sets up the entire foundation of how you will deal with your sin/separation, by trying to make someone else receive the consequences of it, supposedly making you innocent or rather, letting you "get away with" your murderous intentions by having someone else be blamed for them. In this way, the ego creates a state of "fake innocence"... where you seem innocent because someone ELSE has taken the blame for your attack.
Therefore to the ego, innocence is murderous. To the ego, it is possible for the innocent to sin, and for the innocent to insanely destroy others without destroying itself. Can you imagine how ridiculous and twisted it is to believe that someone can be free of responsibility even though they're standing there with the murder weapon having just attacked their brother, believing they are completely free of all consequences? Within the dream, this is insanity, given they did not and will not escape the consequences. The cost of attack is the loss of their own identity.
When we say "do unto others as you would have them do unto you", this does not really mean that other people are separate from you and you should just treat them well. This would mean that maybe, maybe not, they might treat you well in return. This is still a breakdown in cause and effect, leaving open the possibility that even if you treat others well, they may still attack you.
The real meaning of this is that, in the mind aware of its oneness, how it treats others IS how IT treats itself. Therefore it is in its own vested interest ("shared interest") to treat others as it DOES treat itself, because whatever it does to another it IS DOING to itself. This does not rely on others to decide whether or not to reciprocate, because if you treat others with love you WILL experience the effect of love. This is also the true meaning of "karma", not that separate causes will decide to attack you in retaliation, but that YOU attack yourself. All attack is self attack.
What is not love, is murder. Any belief in attack, any sin, any guilt, and anger, any argument, any belief that something applies to others and not you, any way you come between people, any sense of separation, any illusion of being innocent while secretly scapegoating your sin onto others, means you are being murderous. You are trying to "get away with" having sinned and to not suffer the consequences.
The fact is, you do not escape the consequences of sin. If you believe in it, it will destroy you. It's not possible for something to apply to someone else that you don't also believe applies to yourself. You never really get to be "right" and others wrong, because if you are right, you are wrong. You never get to "succeed" in the ego's terms, because that means you have failed. You never get to "win" the ego's game, because that means you have used separation and have lost.
The only way to end the murderousness is to return to love. That means removing the blocks to awareness which prevent you from being able to RECOGNIZE yourself in others, to be aware of your ONENESS with others, and to therefore KNOW that if you do even one tiny thing to hurt anyone, it's going to hurt you. That's a pretty big incentive to always remain loving, because to attack is to be attacked by yourself, and who in their right mind, a sane mind, would want to do that? There is no sense to it.
The fact that what is not love is murder should not be used by the ego right now to make you feel guilty, or to say, well, this means that I'm being murderous because I'm not awake yet, therefore I'm even more sinful. Don't let the ego use this information to accuse you even more than you already have. Simply recognize this is what's happening and continue with your forgiveness of yourself. Murder is not REAL, it is an illusion. There is no REAL attack or REAL separation. It is just a state of being mistaken and thinking that it's possible to accomplish murder and to get away with it, when in fact it's not possible, AND you cannot really hurt who you really are.
There is no murder in heaven. There is no murder in God's reality. Only love is real.