from the writings of Alice A. Bailey and the Master D.K.
Summary: Definition of the Soul - What is the Soul? Can we define it? What is its Nature? - The Christ within - Manifestation of the Subjective Aspect in Man
Definition of the Soul
1. The soul, macrocosmic and microcosmic, universal and human, is that entity which is brought into being when the spirit aspect and the matter aspect are related to each other.
a. The soul therefore, is neither spirit nor matter but is the relation between them.
The soul is the mediator between this duality; it is the middle principle, the link between God and His form.
b. Therefore the soul is another name for the Christ principle, whether in nature or in man.
2. The soul is the attractive force of the created universe and (when functioning) holds all forms together so that the life of God may manifest or express itself through them.
a. Therefore the soul is the form-building aspect, and is that attractive factor in every form in the universe, in the planet, in the kingdoms of nature and in man (who sums up in himself all the aspects) which brings the form into being, which enables it to develop and grow so as to house more adequately the indwelling life, and which drives all God's creatures forward along the path of evolution, through one kingdom after another, towards an eventual goal and a glorious consummation.
b. The soul is the force of evolution itself and this was in the mind of St. Paul when he spoke of the "Christ in you, the hope of glory."
3. This soul manifests differently in the various kingdoms of nature, but its function is ever the same, whether we are dealing with an atom of substance and its power to preserve its identity and form, and carry forward its activity along its own lines, or whether we deal with a form in one of the three kingdoms of nature, held coherently together, demonstrating characteristics, pursuing its own instinctual life and working as a whole towards something higher and better.
a. Therefore the soul is that which gives distinctive characteristics and differing form manifestations.
b. The soul plays upon matter, forcing it to assume certain shapes, to respond to certain vibrations and to build those specified phenomenal forms which we recognize in the world of the physical plane as mineral, vegetable, animal and human, - and for the initiate certain other forms as well.
4. The qualities, vibrations, colors, and characteristics in all the kingdoms of nature are soul qualities, as are the latent powers in any form seeking expression, and demonstrating potentiality. In their sum total at the close of the evolutionary period, they will reveal what is the nature of the divine life and of the world soul, - that oversoul which is revealing the character of God.
a. Therefore the soul, through these qualities and characteristics, manifests as conscious response to matter, for the qualities are brought into being through the interplay of the pairs of opposites, spirit and matter, and their effect upon each other. This is the basis of consciousness.
b. The soul is the conscious factor in all forms, the source of that awareness which all forms register and of that responsiveness to surrounding group conditions which the forms in every kingdom of nature demonstrate.
c. Therefore the soul might be defined as that significant aspect in every form (made through this unfication of spirit and matter) which feels, registers awareness, attracts and repels, responds or denies response and keeps all forms in a constant condition of vibratory activity.
d. The soul is the perceiving entity produced through the fusion of Father-Spirit and Mother-Matter. It is that which in the vegetable world, for instance, produces response to the sun's rays, and the unfolding of the bud; it is that in the animal kingdom which enables it to love its master, hunt its prey, and follow out its instinctual life; it is that in man which makes him aware of his environment and his group, which enables him to live his life in the three worlds of his normal evolution as the onlooker, the perceiver, the actor. This it is which enables him eventually to discover that this soul in him is dual and that part of him responds to the animal soul and part of him recognizes his divine soul. The majority however, at this time will be found to be functioning fully as neither purely animal nor purely divine, but can be regarded as human souls.
The soul therefore may be regarded as the unified sentiency and the relative awareness of that which lies back of the form of a planet and of a solar system. These latter are the sum total of all forms, organic or inorganic, as the materialist differentiates them. The soul, though constituting one great total, is, however, limited in its expression by the nature and quality of the form in which it is found and there are consequently forms which are highly responsive to and expressive of the soul, and others which - owing to their density and the quality of the atoms of which they are composed - are incapable of recognizing the higher aspects of the soul or of expressing more than its lower vibration, tone or color.
What is the Soul? Can we define it? What is its Nature?
Here I shall give but four definitions which will serve as a basis for all that follows.
1. The soul can be spoken of as the Son of the Father and of the Mother (Spirit-Matter) and is therefore the embodied life of God, coming into incarnation in order to reveal the quality of the nature of God, which is essential love. This life, taking form, nurtures the quality of love within all forms, and ultimately reveals the purpose of all creation.
2. The soul can be regarded as the principle of intelligence - an intelligence whose characteristics are mind and mental awareness, which in turn demonstrate as the power to analyze, to discriminate, to separate, and to distinguish, to choose or to reject, with all the implications conveyed in these terms.
I seek in various ways to convey through the symbol of words the significance of the soul. The soul is therefore the son of God, the product of the marriage of spirit and matter. The soul is an expression of the mind of God, for mind and intellect are terms expressing the cosmic principle of intelligent love, - a love which produces an appearance through the nature of mind and thus is the builder of the separate forms or appearances. The soul also, through the quality of love, produces the fusion of appearance and of quality, of awareness and of form.
3. The soul is (and here words limit and distort) a unit of light, colored by a particular ray vibration; it is a vibrating center of energy found within the appearance or form of its entire ray life. It is one of seven groups of millions of lives which in their totality constitute the One Life. From its very nature, the soul is conscious or aware in three directions. It is God-conscious; it is group-conscious; it is self-conscious. This self-conscious aspect is brought to fruition in the phenomenal appearance of a human being; the group-conscious aspect retains the human state of consciousness, but adds to it awareness of its ray life, progressively unfolded; its awareness then is the awareness of love, of quality, of spirit in its relationships; it is God-conscious only potentially, and in that unfoldment lies, for the soul, its own growth upward and outward after its self-conscious aspect is perfected and its group-awareness is recognized.
4. The soul is the principle of sentiency, underlying all outer manifestation, pervading all forms, and constituting the consciousness of God Himself. When the soul, immersed in substance, is simply sentiency, it produces through its evolutionary interplay an addition, and we find emerging quality and capacity to react to vibration and to environment. This is the soul as it expresses itself in all the subhuman kingdoms in nature.
When the soul, an expression of sentiency and quality, adds to these the capacity of detached self-awareness, there appears that self-identified entity which we call a human being.
When the soul adds to sentiency, quality and self-awareness, the consciousness of the group, then we have identification with a ray-group, and there appears the disciple, the initiate and the master.
When the soul adds to sentiency, quality, self-awareness and group consciousness, a consciousness of divine synthetic purpose (called by us the Plan), then we have that state of being and knowledge which is distinctive of all upon the Path of Initiation, and includes those graded Lives, from the more advanced disciple up to the planetary Logos Himself.
But forget not that when we make these distinctions it is nevertheless one Soul that is functioning, acting through vehicles of varying capacities, of differentiated refinements and of greater and lesser limitations, in just the same sense as a man is one identity, working sometimes through a physical body and sometimes through a feeling body or a mental body, and sometimes knowing himself to be the Self - a rare and unusual occurrence for the majority.
The Christ within
When humanity is assured of divinity and of immortality, and has entered into a state of knowledge as to the nature of the soul and of the kingdom in which that soul functions, its attitude to daily life and to current affairs will undergo such a transformation that we shall verily and indeed see the emergence of a new heaven and a new earth. Once the central entity within each human form is recognized and known for what it essentially is, and once its divine persistence is established, then we shall necessarily see the beginning of the reign of divine law on earth - a law imposed without friction and without rebellion. This beneficent reaction will come about because the thinkers of the race will be blended together in a general soul awareness, and a consequent group consciousness will permit them to see the purpose underlying the working of the law.
Let us put this a little more simply. We are told in the New Testament that we must endeavor to let the mind which was in Christ also be manifest in us. We are working towards the perfecting of the rule of Christ on earth; we are aiming at the development of the Christ consciousness and at the bringing in of the rule or law of Christ, which is Love. This will come to fruition in the Aquarian Age, and we shall see brotherhood established on earth. The rule of Christ is the dominance of the basic spiritual laws. The mind of Christ is a phrase conveying the concept of the rule of divine intelligent love, which stimulates the rule of the soul within all forms, and brings in the reign of the Spirit. It is not easy to express the nature of the revelation which is on the way. It involves the recognition by men everywhere that the "mind-stuff," as the Hindus call it, to which their own minds are related and of which their mental bodies are an integral part, is also part of the mind of Christ, the cosmic Christ, of Whom the historical Christ is - upon our planet - the ordained representative. When men, through meditation and group service, have developed an awareness of their own controlled and illumined minds, they will find themselves initiated into a consciousness of true being and into a state of knowledge which will prove to them the fact of the soul, beyond all doubt or questioning.
The Mystery of the Ages is on the verge of revelation, and through the revelation of the soul that mystery which it veils will stand revealed. The scriptures of the world, we know, have ever prophesied that at the end of the age we shall see the revelation of that which is secret, and the emergence into the light of day of that which has hitherto been concealed and veiled. This, our present cycle, is the end of the age, and the next two hundred years will see the abolition of death, as we now understand that great transition, and the establishing of the fact of the soul's existence. The soul will be known as an entity, as the motivating impulse and the spiritual center back of all manifested forms. The next few decades will see certain great beliefs substantiated.
Individual man and his soul are also attempting to come together, and when that event is consummated the Christ is born in the cave of the heart, and Christ is seen in the daily life with increasing power.
Manifestation of the Subjective Aspect in Man
One of the objects of evolution is that the subjective reality should eventually be brought forward into recognition. This can be expressed in several symbolic ways, all of them dealing with the same one fact in nature:
The bringing to the birth of the Christ within.
The shining forth of the inner radiance or glory.
The demonstration of the 2nd or the Love aspect.
The manifestation of the solar Angel.
The appearing of the Son of God, the Ego or the Soul within.
The full expression of buddhi, as it utilizes manas.
This emergence into manifestation is brought about through what is understood by the following terms:
The refining of the bodies which form the casket or sheath hiding the reality.
The process of 'unveiling' so that one by one those bodies which veil the Self are brought to a point where they are simply transparencies, permitting the full shining forth of the divine nature.
An expansion of consciousness, which is brought about through the ability of the self to identify with its real nature as the Onlooker, and no longer regarding itself as the organ of perception. 
