Following the evolutionary sequence, the Upanishad next brings forth the power of the world of life, the vital world, in the form of the god Vayu. This principle of manifestation is not limited to our human definition of “life”; rather it is a principle of development, expansion and movement, which includes what we would call “life” but goes beyond it in the universal creation.
Verses 7-10 of the third part of the Kena Upanishad: “Then they said to Vayu, ‘O Vayu, this discern, what is this mighty Daemon.’ He said, ‘So be it.’ He rushed upon That; It said to him, ‘Who art thou?’ “i am Vayu,’ he said, ‘ and I am he that expands in the Mother of things.’ ‘Since such thou art, what is the force in thee?’ ‘Even all this I can take for myself, all this that is upon the earth.’ That set before him a blade of grass, ‘This take.’ He went towards it with all his speed and he could not take it. Even there he ceased, even thence he returned; ‘I could not discern of That, what is this mighty Daemon.’ ”
Sri Aurobindo comments: “Another god rises to the call. It is Vayu Matarishwan, the great Life-Principle, he who moves, breathes, expands infinitely in the mother element. All things in the universe are the movement of this mighty Life; it is he who has brought Agni and placed him secretly in all existence; for him the worlds have been upbuilded that Life may move in them, that it may act, that it may riot and enjoy. If this Daemon be no birth of Matter, but some stupendous Life-force active whether in the depths or on the heights of being, who shall know it, who shall seize it in his universal expansion if not Vayu Matarishwan?”
“This is Vayu Matarishwan and the power in him is this that he, the Life, can take all things in his stride and growth and seize on them for his mastery and enjoyment. But even the veriest frailest trifle he cannot seize and master so long as it is protected against him by the shield of the Omnipotent. Vayu too returns, not having discovered. One thing only is settled that this is no form or force of cosmic Life which operates within the limits of the all-grasping vital impulse; it is too great for Vayu.”
Sri Aurobindo, The Upanishads, Kena Upanishad and analysis, pp. 104-106, 171-176
Sri Aurobindo Studies 