The principle behind transformation is that our limited Nature (though stupendous when we see her workings) has behind its seemingly mechanical workings a perfect Intelligence, a Supernature, a Conscious Force prompting and pushing from behind, expressing itself as an intuition and a wonder in her workings. It is this greater Intelligence that governs and directs the manifold operations of Nature keeping a cosmic order, keeping each species within its limits and yet providing for its survival and growth.
In man, the limits begin to fall which is part of the original plan. That is why man is never fully satisfied and he tends to seek further which is the basis of his conscious progress bringing in new knowledge and new in the process manifest new possibilities. Yoga is a special and extreme application of this conscious thirst for endless progress and the need for perfection within man. The extreme possibility being that since we carry the Source of Creation within ourselves we can be one with IT.
But before becoming one with IT we must have some contact with IT. Faith and aspiration is the first proper contact with this greater Reality. In ignorance, faith turns into a fixed and formal, often narrow and dogmatic belief system. Aspiration changes into mechanical and formal, ritualistic prayer which do not have the power to bring us in contact with the Reality we call God. They show us His shadow, in the form of various conceptions but not the body of the King.
By the force of aspiration and concentration upon the Divine we can succeed in piercing the magic fence bringing thereby an initial contact. Once an opening is made, however small, it seldom closes. The workings of the Divine Force keeps increasing it, faster or slower depending upon our sincerity.
But how are we to concentrate upon That which escapes all conceptions and perceptions. It is here that we have the mystery of the Divine descents in humanity, the Avatar or the Divine wearing a human shape. Each Avatar of which Krishna, Buddha, Christ form a part, comes to facilitate the contact and open doors to some new possibility. By concentrating upon the Avatar, on His Name and Form, through worship and surrender we can easily enter into contact with the greater Reality that the Avatar represents. He becomes the door so to say. Masters can take us outside the manifestation into Nirvana at most but within the manifestation, they cannot exceed the limits set by Nature which are pushed step by step further by Avatar.
It is in this sense that we have to regard the Mother and Sri Aurobindo who came to push the limits to the last making our finite life one with the Infinite, our human nature one with the Divine Supernature. The Mother embodies this Supernature and by remembering Her, by taking Her Name, by meditating upon Her, by offering all our actions to Her, through love, through reading, through prayers directed towards Her we start building bridges and contacts. The rest happens automatically by Her Force entering our human nature into those parts in which the contact has been made through the offering. Later the Divine Force enters even the darkest corners even in hidden corners of our being laying bare everything, transforming everything. The process remains the same but as more and more parts are engaged in the yoga the offering too becomes wider and more complete until all becomes one with Her and one with all through Her.