In A Course in Miracles, forgiveness is a movement away from believing that illusions are true and real, towards recognizing that they are in fact not true or real. This becomes clear when your awareness increases sufficiently to reveal a larger truth, which shows you the ways in which the "smaller truth", i.e. illusory lies, are in fact limited and untrue.
Forgiveness, as a process, is also a movement from unawareness, in which you don't see clearly or fully, to a state of expanded awareness where you see more of the whole picture and with greater accuracy. As you go through this, what seemed to be true of your illusions starts to be recognized as being not as true as the larger truth.
It's a matter of becoming clear about what REALLY is true, and what is actually false. Getting truth and illusions confused is the ENTIRE content of the ego, and the entire content of the separation from God - which is you trying to make illusions become reality.
As you become more aware of what the truth really is, and less convinced about what the truth is not, your discernment of true vs false becomes clearer. You learn to recognize the truth for what it is (not the illusion you thought it was), and recognize the illusion for what it is (not the reality you thought it was).
Through forgiveness you will eventually reach a truly, fully "forgiving" state of awareness, which recognizes ALL of the truth, which is that nothing has really happened, there is only innocence, and therefore there is nothing to forgive.
Now, there are a couple of pieces of the puzzles of performing miracles which I did not really get, but which certain Christian practitioners tried to describe. They would say that you have to a) believe in Jesus ("be a believer"), and b) have "faith". Since their belief in Jesus was heavily wrapped in Christian theology, I had trouble discerning exactly WHAT it was about Jesus that I was supposed to believe - such as that He died for our sins and such, which is not an ACIM teaching. I also have never really 'got' what faith means, because it was never explained in a clear context.
But I've become clearer on this now.
The only way that "believing in Jesus" and "having faith" become meaningful, is when you can discern that the ENTIRE WORLD IS AN ILLUSION. It is necessary to have a really strong clear distinction between what is TRUE, and what is FALSE. So as you go about your life believing in the world, (even if you're trying to learn not to believe in it you probably still do), while you're in this sort of in-between phase of "some of the truth is true, but some of it I don't get", you will also be similarly confused about what it means to believe in Jesus, and what faith is.
If parts of the world are real to you, in spite of what you might claim otherwise, this HAS to mean that you in part also believe that God is not entirely real. It also means that you have 'faith in' the ego, and faith in sickness and death.
Now, this isn't something that people want to admit but, the simple fact is, either you believe that God is real, fully, or in some way you don't believe it. And that displaced belief will be put into a conviction that the ego is real - that it is truth, and that everything it claims is true. That will go on to mean that when shit happens in the world and it seems real, part of you will be trying to look to God for a way out of it, but part of you will be attached to believing in it. And so you are now torn, or your faith is divided. And Jesus says faith cannot serve two masters.
So what needs to happen is, through proper forgiveness, we need to become REALLY CLEAR about the distinction between reality, and illusions. We can' have this mishmash of partial reality and partial illusion. It will confuse us and rob truth of meaning.
To be able to believe in Jesus, means that you believe Jesus is 100% reality, He is 100% love, He is 100% truth, 100% immortal, 100% innocent, 100% at peace etc. He shares this truth with God 100%.
IF that is true, if that's your definition of truth, then it HAS to mean, that anything not of God is not truth. So now you need to be very clear, WHAT is not of God? Because if you go on believing God created the world, and yet the world seems to be the place where things fuck up big time, then... well, now you are super confused. And of course you are confused because it makes no sense that God would create a world with sickness in it, because that means God creates sickness. So now if you were to follow that truth, and you were trying to find some healing or peace from experiencing sickness, how the heck would you have any kind of power to turn to if that power believes in sickness? You'd be hopeless.
So... to believe in Jesus means to believe in God, that God is the one and only truth, and only things which are completely in accord with unconditional love are of God. Nothing else. Absolutely nothing else at all can be permitted to take up the label of "real" or "true".
So then you have to ask yourself, did God create the world? No. He did not. So that means the world is not real. And that's mind-blowing, if you really take in deeply. It completely undermines your entire view of reality - or rather, your mistaken view in which you think illusions are reality. Because all this time you've been thinking you're living in a 'real' world and now you find out, it's a tricking illusion pretending to be real!
But this is how you can then have faith. You can have faith because, now that you believe in God's truth, and you know that God's truth is the only truth, and that this world is NOT a part of God's truth, that means whenever any shit happens in the world, you can BYPASS it, OVERLOOK it (forgiveness), and HOLD STRONG to the truth as God would have it be. That means, NO MATTER WHAT is in front of your face, no matter what happens, no matter how serious it seems, no matter how final - even death, YOU DO NOT BELIEVE IN IT, because believing in it would have to mean - you really do not believe in God all the way.
But if you DO believe in God, then.... no matter what happens, no matter how serious, you do NOT pay it attention, you do NOT believe in it, and you instead express and extend GOD'S REALITY in place of it. You cancel it out. You overwrite it. You clarify that the problem is NOT real, is NOT the truth, and you replace it with love. This shows the nothingness of the illusion, puts everything in its correct order, and corrects all confusion. It also produces miracles.
So you have faith by believing that God's truth is true, and that this is shared by Jesus.... and you have faith by holding true to that fact regardless of how the world seems to be. The only question of your faith wavering is when you believe the illusion enough that your belief in God's power wavers, and that means you've temporarily forgotten that God's truth is true. You've believed in the ego again. So you lose faith when that happens.
This kind of faith in God is not blind faith or just 'hope'... it is CERTAINTY, it is KNOWING, it is TRUTH, and it is CORRECTION.
Holy Spirit interjected while writing that the word "trust" is really what faith means. Trusting God. Trusting the real truth. Trusting that BECAUSE of what the truth is, that "this problem" is not insurmountable or irreversible. It is that knowing of the truth, that trust in the truth, which powers miracles.
So forgiveness leads you to miracle mindedness, a clarity about what is true and what is false gives you miracle mindedness, and a certainty about the truth being true (and that therefore the world is not real) gives you the foundation for faith. Your trust/faith in God's Way gives you miracle-working capabilities.
To get there you're going to have to question the validity of every way that you're trying to find truth in the world, because it means that you're looking for truth in an illusion. It means you're not clear yet about what is true and what is false. The world is false - head's up!. Entirely false. It is entirely an illusion that doesn't really exist or mean anything at all. Every time you 'seek' for truth in it, you will not find it, because it is not there. You need to learn to stop trying to do that and instead believe in God.
The miracles will flow from there.