So to generalize what the human soul is, I will try to explain it in my own words, for while it is covered in almost every Alice Bailey book, it is not plainly laid out. The human soul is a very highly being from the Deva realm. It can be reffered to as the soul, the solar angel or an Agnishvatta. A human comes into exsistence as a personality with a soul & a Monad. He or she is what is called uninitiated or animal man. It has love for itself & relates life to how things or events relate to itself. To step forward on the wheel of life, he must learn to express love for someone more than he loves himself & have some small level of intelligent discernment. When he can do this, which usually taskes some number of lifetimes, he receives a level one initiation. What is called the personality, the lower level man, has a level of vibration, which is lower than the level of his etheric body, which is the sumtotal of the chakras & the etheric web. The soul at this higher vibration, has to wait for lifetimes while the personality raises its vibration through love. Our Solar Logos is a second ray (Love-Wisdom) being which is why that is so important. The monad also waits as it is unable to contact the other two due to the difference in vibration, because it resides an an even higher vibration. As Level one is neared the soul starts to build the petals of the outer row of the Egoic Lotus As that level is reached an initiation called the Birth is given by Lord Christ. As the personality is evolving the soul has more & more opportunity to assist the raising of the consciousness of the personality to a higher level, thereby raising the personality to a higher level. The souls purpose is to provide consciousness & bridge the gap between the personality & the Monad, thus the required building of the Egoic lotus & the Antahkarans in conjunction with the soul.
 From The Treatice on White Magic, Page 34 “ The Soul, macrocosmic & microcosmic, universal & human, is the entity which is brought about when the spirit aspect & the matter aspect are related to each other.
 a. The Soul is therefore is neither spirit nor matter but the relation between them.
 b. The Soul is the mediator between this duality; it is the middle principle, the link between God & his form.
 c. Therefore the Soul is another name for the Christ principle, whether in nature or in man.
The soul is the attractive force of the created universe & (when functioning) holds all forms together so that the life of God manifest or express itself through them.”
Page 36 b. States ”the Soul plays upon matter,forcing it to assume certain shapes, to respond to certain vibrations & to build those specified phenomal forms for which we recognize in the world of the physical plane as mineral, vegatable, animal or human & for the initiate certain other forms as well.”
  Page 47 States “The anima mundi is that lies back of the web of life. The latter is but the physical symbol of that universal soul; it is the outer & visible sign of the inner reality, the concreation of the sensitive responsive entity that links spirit & matter together. This entity we call the universal Soul, the middle principle from the standpoint of the planetary life.” “The individual man, we call it the mediating principle for the Soul of mankind is not only an entity linking spirit & matter, & meditating between Monad & personality, but the Soul of humanity has a unique function to perform in mediating between the higher three kingdoms in nature & the lower three.”

 The importance of the Solar Angel is conveyed on page 88 of “The Treatice on White Magic” it states “ In the early history there was a great crisis which we call individualization. At that time the Solar Angels, in response to the demand or pull from the race of animal-men (as a whole, note that), sent a portion of their energy, embodying the quality the quality of mentalization, to these animal-men.They fecundated, if I might so express it, the brain. Thus was humanity brought into being." “Another strong is being exerted upon the Solar Angel which this time will produce a second fecundation. This will give to man those qualities which will enable him to transcend human limitations & become a part of the fifth or spiritual kingdom in nature. The first effort of the solar angel turned animal-men into human beings: the second will turn human beings into spititual entities, plus the gained experience in the human family.”

 From Page 89 it is stated “All forms of life under the force of evolution pass from initiation to initiation & the soul is not exempt from the process. Just as the soul of animal-man became united with another divine principle & so brought into being the fourth kingdom in nature, so the soul in humanity is seeking contact with another divine aspect. When that contact is made the kingdom of God will come on earth; the physical plane will thereby be transformed & that peculiar period, presented symbolically under the term millenium will come.
The knowers of God in that era will preponderate over those who are simply aspiring to that knowledge & their contact & the results of the force they transmit will be felt in all kingdoms of nature. Dominion over all forms & the power to act as transmitters of that spiritual energy we call love is the promised reward of the triumphant Solar Angels & the prized goal of their meditation work.The sons of God will triumphant on earth in full incarnated expression & will bring light (therefore life) to all manifested forms.”