"I could not atone for MYSELF ALONE. Listening to one Voice implies the decision to share It in order to hear It yourself. The Mind that was in me is still irresistibly drawn to EVERY MIND CREATED BY GOD, because God's Wholeness is the Wholeness of His Son. You cannot be hurt, and do not want to show YOUR BROTHER anything except your wholeness. Show him that he cannot hurt you and hold nothing against him, or you hold it against yourself. This is the meaning of turning the other cheek."
"Oneness is simply the idea God is. And in His Being, He encompasses all things. NO MIND (implying there are many) holds anything but Him (therefore he created many minds)."
"Miracles make MINDS one in God. They depend on cooperation because the SONSHIP is the SUM OF ALL THAT GOD CREATED. Miracles therefore reflect the laws of eternity, not of time."
"God speaks for you in answering your question with these words: I walk with God in perfect holiness. I light the world, I light my mind and ALL THE MINDS WHICH GOD CREATED ONE WITH ME"
"ONE CHILD OF GOD (implying there are many) is the only teacher sufficiently worthy to teach ANOTHER (there are many!). One Teacher is in ALL YOUR MINDS, and He teaches the same lesson TO ALL. He always teaches you (one such mind) the inestimable worth of EVERY SON OF GOD, teaching it with infinite patience born of the infinite love for which he speaks."
"The Holy Spirit is the spirit of joy. He is the Call to return which God blessed THE MINDS OF HIS SEPARATED SONS. This is the vocation of the mind."
"Let us not wander into temptation, for the temptation of the Son of God is not Your Will. And let us receive only what You have given, and accept but this INTO THE MINDS WHICH YOU CREATED AND WHICH YOU LOVE. Amen."
I don't know about you guys-n-gals but it sounds to me very clearly that there are MULTIPLE SONS and MULTIPLE MINDS. And that the presence of multiple minds is completely natural and normal because God CREATED THEM. Therefore EACH ONE has its "own mind". Each mind may well be "one" or in harmony with other minds, but there are still many minds, and each still has its own potential to choose whether to do God's will or not.
This is why some parts of the Course refer on ONE LEVEL to the ONE SON OF GOD, and on another level to the MANY INDIVIDUAL SONS (or souls).
References to BROTHERS who are one with God:
"You are afraid of God because you fear your BROTHER. This BROTHER who stands beside you still seems to be a stranger."
"Some bitter idols have been made of him who would be only BROTHER to the world. Forgive him your illusions, and behold how dear a BROTHER he would be to you. For he will set your mind at rest at last and carry it with you unto your God."
"To know your BROTHER is to know God."
"Miracles unite you directly with your BROTHER."
"One moment of real recognition makes everyone your BROTHER."
"Any BROTHER with whom you have a limited relationship, you hate."
"Don't deny yourself the message of relief that every BROTHER offers you now."
"It is not up to you to change your BROTHER, but merely to accept him as he is."
"In your BROTHER is the light. See him as sinless, and there can be no fear in you."
"The miracle enables you to see your BROTHER without his past, and so perceive him as born again."
"Your BROTHER does not have to be aware of the Holy Spirit in himself or in you for the miracle to occur."
"What you acknowledge in your BROTHER you are acknowledging in yourself, and what you share you strengthen."
"The miracle acknowledges everyone as your BROTHER and mine. It is a way of perceiving the universal mark of God."
"Because the miracle worker has heard God's Voice, he strengthens It in a sick BROTHER by weakening his belief in sickness, which he does not share." (again confirmation that your brother can refuse healing even if you are healed)
"Where there is love, your BROTHER must give it to you because of what it is. But where there is a call for love, you must give it because of what you are." (similarly again, you give love to those who lack it)
"How willing are you to forgive your BROTHER? How much do you desire peace instead of endless strife and misery and pain? These questions are the same, in different form."
"Trials are but lessons you failed to learn presented once again, so where you made a faulty choice before you now can make a better one. In every difficulty Christ calls to you and gently says, My BROTHER, choose again."
"If you attack error in another, you will hurt yourself. You cannot know your BROTHER when you attack him. Attack is always made upon a stranger. You are making him a stranger by misperceiving him, and so you cannot know him. It is because you have made him a stranger that you are afraid of him. There are no strangers in God's creation."
"Forgiveness recognizes what you thought your BROTHER did to you has not occurred. It does not pardon sins and make them real. It sees there was no sin. And in that view are all your sins forgiven. What is sin, except a false idea about God's Son? Forgiveness merely sees its falsity, and therefore lets it go. What then is free to take its place is the will of God."
"Not one does Christ forget. Not one He fails to give you to remember, that your home may be complete and perfect as it was established. He has not forgotten you. But you will not remember Him until you look on all as He does. Who denies his BROTHER is denying Him, and thus refusing to accept the gift of sight by which his Self is clearly recognized, his home remembered and salvation come."
It seems to me what the One Son of God, as Christ, is considered a BROTHER to the MANY SONS, who were also created (souls?) as extensions of him/god, ... and that at times the course refers to them on an equal footing because they are made of God-stuff equally, even though Christ appears to be a "larger" identity than the individual sons. But Christ+the individual sons make up "the sonship". So the sonship is not just the individual sons, it also includes the one son, and all are considered equal brothers in that sonship.