Sweet Mother, here it is written: “But so long as the lower nature is active the personal effort of the sadhaka remains necessary.” I didn’t understand here “so long as the lower nature is active”. How?
Generally, the lower nature is always active. It is only when one has surrendered completely that it stops being active. When one is no longer in his lower consciousness, when one has made a total surrender, then the lower nature is no longer active. But so long as it is active, personal effort is necessary.
In fact, so long as one is conscious of one’s own self as a separate person, personal effort has to be made. It is only when the see of separation is lost, when one is not only completely surrendered, but completely fused in the Divine that there is no longer any need of personal effort. But so long as one feels that one is a separate being, one must make a personal effort. This is what he calls the activity of the lower consciousness.
The Mother – Questions and Answers: CWM, Vol.6, pp220-21
In all that is done in the universe, the Divine through his Shakti is behind all action but he is veiled by his Yoga Maya and works through the ego of the Jiva in the lower nature.
In Yoga also it is the Divine who is the Sadhaka and the Sadhana; it is his Shakti with her light, power, knowledge, consciousness, Ananda, acting upon the adhara and, when it is opened to her, pouring into it with these divine forces that makes the Sadhana possible. But so long as the lower nature is active the personal effort of the Sadhaka remains necessary.
Sri Aurobindo – The Mother with Letters on The Mother: CWSA, Vol. 32, p6