I have edited the following italicised section from William Arkle’s A Geography of Consciousness pp. 123-4:
Mortal Man’s right to, and experience of, autonomy is a very destructive and dangerous process in that it is paved with ugly and inharmonious desires and ideas. If the Angelic stage of evolution was also open to this reactive phase, the result would be total destruction and collapse of the necessary field of earthly experience.
So, while we Humans make the great sacrifice of suffering and pain to achieve an autonomous and individual divine nature, so the Angels make the great sacrifice which is to create and maintain the necessary ground for our Human experience; and they clean up the mess we make in the course of this experience. This work requires them to remain always in harmony with the divine purpose and aspiration, and consequently does not properly allow them the experience of objective valuation which ultimate understanding requires.
Such is the interpretation given to the parable of the Prodigal Son. The Prodigal is the Human who is bound to sin for a reason he does not understand, but which – in the end – gives him knowledge of very great value.
But his Brother, who does not sin and who does not venture off into the wilds of poverty and hunger, does not experience the pain and misery of this hunger; and therefore does not value that which is hungered-for in quite the same way. The Brother [like the Angels] is never lost and never has cause to be rejoiced-over; for he never returns of his own accord with this priceless treasure, and his Father in Heaven never has anxiety about him.
The Prodigal Son represents us - represents mortal Men; the Brother represents the Angels.
Such Angels I conceive to be pre-mortal spirit Children of God (i.e. men and women such as ourselves, but before we were incarnated) – whose ‘job’ includes vital assistance in making and maintaining the earth and creation for incarnate mortal Men to inhabit.
Our world is where we may experience the consequences of our agency and sin; such that we may ultimately repent, return, and bring-home the precious treasures won from our sufferings and death.
That is the sacrifice of mortals.
The premortal Men/ Angels vital role is to help mortal Men, and to ‘clean-up the mess’ created by mortal Men so that mortal life does not rapidly self-destroy and collapse.
Such a job entails absolute concordance with the divine will and purpose; therefore the Angels must have limited agency and, consequently, delayed spiritual progression. They must patiently wait their turn for incarnation.
And that is the sacrifice of the Angels.