The spiritual force from the heights attempting to transform the lower nature turns out to have a long, arduous and complex work ahead of it. The lower nature is not a blank slate upon which the new understanding, responses, actions & feelings can be written. Rather, all of the accumulated habits, patterns and lines of action of the lower nature are fully entrenched and not willing to cede their control easily or without an effort which must be both persistent and extremely detailed.
“Every part of our being has to be taken in its own nature and character, with all the moulds and writings of the past still there in it: each minutest portion and movement must either be destroyed and replaced if it is unfit, or, if it is capable, transmuted into the truth of the higher being.”
Things become even more difficult if the force is descending as a result of some “pulling” before the psychic transformation has been thoroughly effected. In this case, there is a danger of the lower nature not being prepared to “hold” the force and this can lead to mental imbalances, vital aggrandised ambitions, or nervous or physical breakdowns of one kind or another. In such a case, the power withdraws, but the results of its impact are left behind.
“Even if none of these more disastrous faults or errors should take place, still the numerous mistakes of reception or the imperfections of the vessel may impede the transformation. The Power has to come at intervals and work meanwhile behind the veil or hold itself back through long periods of obscure assimilation or preparation of the recalcitrant parts of Nature; the light has to work in darkness or semi-darkness on the regions in us that are still in the Night. At any moment the work may be stayed, personally for this life, because the nature is able to receive or assimilate no more,–for it has reached the present limits of its capacity,–or because the mind may be ready but the vital, when faced with a choice between the old life and the new, refuses, or if the vital accepts, the body may prove too weak, unfit or flawed for the necessary change of its consciousness and its dynamic transformation.”
Sri Aurobindo, The Life Divine, Book 2, Part 2, Chapter 25, “The Triple Transformation”