If there’s one thing that’s absolutely vital to understand about A Course in Miracles, it’s that it’s all about the practice of forgiveness. And not any kind of forgiveness either- especially the traditional sense in which forgiveness is typically understood.
The Course distinguishes between what we typically think of as forgiveness, as false, or forgiveness-to-destroy, and its own definition of forgiveness as true, or forgiveness-to-heal. The core difference between the two is that true forgiveness is based on the idea that there is no world- a foundational metaphysical concept of ACIM. The world of form and change in which we think we exist as bodies, is in fact not true, and never has been. So in turn, whatever you think has upset/irritated/angered you, ultimately never happened. So forgiveness then becomes more a way of perceiving that acknowledges that, hey, none of this is actually happening or has happened, because I’m not a body, and neither is anyone else i think i see as outside of me.
So if I’m not a body, what exactly am I? Jesus assures us that we are spirit and our mind is part of God’s. Why? Because we are still as God created us (even though it does appear otherwise- let’s be honest!). In short, the Course’s message is always about validating the fact that we never separated from God, despite all our (very convincing) evidence and experiences to the contrary. It’s not about pretending we don’t think we’re here in the world of form, but about mentally remembering that we are still one with God, which in effect, denies our subconscious denial of God and our awareness of our true reality in Him.
The reason then that the practice of true forgiveness leads to happiness is because God, as the Course defines Him, is the very idea and experience of Happiness. As a non-dualistic teaching, it’s important to grasp that ACIM is saying that our apparent world of form is false, illusory- the equivalent of a dream- whereas God is all there is. He is love, joy, peace, and goodness without opposite; unchanging and infinite. This is our source and our home. And the only way back is to remember that we’re already there- we’ve never left- by undoing the erroneous idea that we have left, and the incredible guilt and fear that belief created in our mind.