God is, and there is nothing else. There is only God; all seeming else is a lie.

"Why must the inner, spiritual kingdom come _first_?

Because _the inner controls and determines the outer_.
 It is just as simple as that.
However, the mass of mankind,
while giving lip service to this truth,
does not actually realize it,
which accounts for the neuroses of the masses." Vernon Linwood Howard

THERE IS A straight white line of absolute Truth upon which each one must walk if he would
have demonstration. The slightest swerving in either direction from this line results in non-demonstration, no matter how earnest or intense one may be.
The line is this: There is only God; all seeming else is a lie.
Whosoever is suffering today from sickness, poverty, failure--any kind of trouble--is believing the lie. Unadulterated Truth ~ Emilie Cady's How I Used The Truth

The fear of losing the individual, special self that is our personal identification is so great that we resist the direct learning of Atonement's simple message of love: God is, and there is nothing else. We therefore require indirect or reflected expressions of this truth. These expressions are the kind and gentle dreams of forgiveness:

So fearful is the dream, so seeming real, he [God's Son] could not waken to reality without the sweat of terror and a scream of mortal fear, unless a gentler dream preceded his awaking, and allowed his calmer mind to welcome, not to fear, the Voice that calls with love to waken him…(T-27.VII.13:4).

In these gentle dreams of our everyday experiences, our Teacher shows us how what we perceive external to us is nothing more than the mind's projected thoughts we have first chosen to put our faith in (e.g., T-21.in.1:1-5; W-pI.23.3:1-2). This helps us recognize that the way we perceive another is how we perceive ourselves, and why would we choose to remain in hell in order to justify our attacks on someone who is the same as we? As different as we appear to be as bodies, the truth is that as minds we are the same: everyone who comes here has the same wrong mind, right mind, and decision maker.

This corrected or healed perception, Christ's vision, dissolves the ego's raucous shrieks and opens our ears to hear Heaven's still, small Voice we had denied for so long. Softly, the hush of Heaven is heard in our whispering to the Holy Spirit for help, expressing the willingness to look past the frantic and frenetic noises of love and hate to the gentleness of everyone's call for help. The key to the practice of our indirect learning is kindness, for this alone unblocks our ears, washing clean the static of judgment that we may hear in our erstwhile special love and hate partners their plaintive call to return home.

It is imperative as we journey on with Jesus that we keep in mind that Heaven does not present itself to us as Handel's Hallelujah Chorus, trumpets resplendent in their greeting and choruses of angels singing Hallelujahs in joyous welcome. Rather, we hear the whispered Voice of Atonement that reflects the whispering of our little willingness to hear. Unable to love here—unambivalent love is not possible in this world of bodies (T-4.III.4:6)—we need its earthly reflection of forgiveness (W-pI.60.1:4-5) to lovingly lead us to the God we never left. Again, these are the happy and nonjudgmental dreams that will ultimately awaken us:

Dream softly of your sinless brother, who unites with you in holy innocence. And from this dream the Lord of Heaven will Himself awaken His beloved Son (T-27.VII.15:1-2).

What needs to be done to erase all thoughts of sin from our holy minds? Nothing. We simply look with kindness at one who had been the hated object of our mind's displaced guilt. Forgiveness entails seeing that just as our anger (projected guilt) was made up—the ego's hateful interpretation of what in truth was our brother's call for help in learning he is forgiven—so too was our guilt. We are not Sons of God in sin and guilt, but His Sons in holiness and love. From WHISPERING TO THE ATONEMENT
The Gentle Way of A Course in Miracles

We had, studied various religions but were not satisfied to accept any of them wholly.  We said: "There are so many religions. Let us go ahead for ourselves; let us do what we think is best, and ask God to be with us and to lead us and guide us."  We began our work in one little room down town, and it has grown gradually. We have studied many "isms," many cults. . . . We have borrowed the best from all religions. . . We found that we could group under the name, Unity, all the different cults that we had thought out and worked out.  In this way we established the fundamentals of the doctrine called Unity. Charles Fillmore 1923