“Healing and Atonement are not related; they are identical. There is no order of difficulty in miracles because there are no degrees of Atonement. It is the one complete concept possible in this world, because it is the source of a wholly unified perception. (M-2.1)”
So healing equals Atonement! How obvious! Healing is a central concept of A Course in Miracles, and the undoing that Atonement comprises does indeed lead to healing in this world. This world knows perception, not usually knowledge (which is reserved for the “real world”), and a unified perception will mean that the mind is no longer split between the ego and your right mind.
“No degrees of Atonement” means that it is an all-or-nothing concept. We are either healed completely or not at all, though in time we will know a lessening of the ego, usually, over weeks, months, or even years.
We want to have a unified perception of this world, for this means that we are heading into Awakening, or enlightenment—when God deems us ready. There are things that we can do that will hasten God’s action. We cannot, though, dictate to Him. But we can leave behind judging, attacking, making plans against contingencies to come (unless these plans are endorsed by the Holy Spirit). And these three actions will move us closer to the ultimate choice in God to reach down and lift us up to Awakening.