The perfection of the instruments of the being provides a foundation for effective action, but in and of itself it does not provide guidance, direction or the action of the higher force. The process of the Yoga requires the seeker to go beyond the limits of the human ego-personality and invoke the Divine Shakti to work through the instrument under the direction of the Master of the Shakti, the Lord of the being, or Ishwara.
Sri Aurobindo observes; “The force at work in us must be the manifest divine Shakti, the supreme or the universal Force unveiled int he liberated individual being,…, who will be the doer of all the action and the power of this divine life…. The One behind this force will be the Ishwara, the Master of all being, with whom all our existence will be in our perfection at Yoga at once of oneness in being and of union in various relations of the soul and its nature with the Godhead who is seated within us and in whom too we live, move and have our being. It is this Shakti with the Ishwara in her or behind her whose divine presence and way we have to call into all our being and life. For without this divine presence and this greater working there can be no Siddhi of the power of the nature.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 15, Soul-Force and the Fourfold Personality, pg. 712