The psychic being can at first exercise only a concealed and partial and indirect action through the mind, the life and the body, since it is these parts of Nature that have to be developed as its instruments of self-expression, and it is long confined by their evolution. Missioned to lead man in the Ignorance towards the light of the Divine Consciousness, it takes the essence of all experience in the Ignorance to form a nucleus of soul-growth in the nature; the rest it turns into material for the future growth of the instruments which it has to use until they are ready to be a luminous instrumentation of the Divine. It is this secret psychic entity which is the true original Conscience in us deeper than the constructed and conventional conscience of the moralist, for it is this which points always towards Truth and Right and Beauty, towards Love and Harmony and all that is a divine possibility in us, and persists till these things become the major need of our nature. It is the psychic personality in us that flowers as the saint, the sage, the seer; when it reaches its full strength, it turns the being towards the Knowledge of Self and the Divine, towards the supreme Truth, the supreme Good, the supreme Beauty, Love and Bliss, the divine heights and largenesses, and opens us to the touch of spiritual sympathy, universality, oneness.
—Sri Aurobindo, The Life Divine, p. 239
It is in each of you the deep inner being which you have to find in order that you may come in contact with the Divine in you. It is the intermediary between the Divine Consciousness and your external consciousness; it is the builder of the inner life, it is that which manifests in the outer nature the order and rule of the Divine Will.
The Mother, MCW, Vol. 3, p. 62
The psychic being is a spiritual personality put forward by the soul in its evolution; its growth marks the stage which the spiritual evolution of the individual has reached and its immediate possibilities for the future. It stands behind the mental, the vital, the physical nature, grows by their experiences, carries the consciousness from life to life. It is the psychic Person, caitya puruṣa. At first it is veiled by the mental, vital and physical parts, limited in its self-expression by their limitations, bound to the reactions of Nature, but, as it grows, it becomes capable of coming forward and dominating the mind, life and body. In the ordinary man it still depends on them for expression and is not able to take them up and freely use them. The life of the being is animal and human, not divine. When the psychic being can by sadhana become dominant and freely use its instruments, then the impulse towards the Divine becomes complete and the transformation of mind, vital and body, not merely their liberation becomes possible.
—Sri Aurobindo, Letters on Yoga, pp. 285-86