A principal tenet in the Course is the assertion that what we would give to others is actually also given to ourselves. This dynamic can be understood on more than one level.
In the most all-encompassing way, we are the other, because we are one in God. We are all brothers and sisters under the skin. So when we feel this kinship in our especially loving moments, we are seeing the truth. In a second way of viewing, we see the playing out of the Golden Rule: Do unto others as you would have them do unto you. We see why this rule is important, the underlying truth that supports it. Because of projection, we will believe that what we think of others or do to others is being done to ourselves. Jesus sees this whole world as illusory and in the great projection that made it, we see our real desires played out in our everyday dramas. Thus, what we do unto others we do unto ourselves. There is no greater truth, no more persuasive argument to treat our fellow human beings with kindness and love. What we sow, we reap. As Jesus says (in the negative), “Seek to deny and you will feel denied. Seek to deprive, and you have been deprived.” (T-25.IX.8:2-3)
If we do not believe another worthy of forgiveness, we will not believe ourselves worthy either. Having refused forgiveness for ourselves, we will never offer it freely. So we have set up a vicious circle for ourselves. The only way out of this vicious circle is reject conflict and ask for help and guidance from a Power greater than ourselves. This Power—the Holy Spirit—will make it easy on ourselves. We can effortlessly to forgive when we come to believe that the deed that we feel unworthy of forgiveness, has been illusory. Our real Selves have not been touched nor harmed in any way. Out real life has continued unabated.
Only a loving God could come up with such a solution. We would have already destroyed ourselves if our deeds had real consequences. We live in an illusion that allows all choice, but at the same time that saves us from ourselves. And through these means we learn, finally, what is truly real and of value, worthy of further extension in Reality.