This is the first, the central teaching: the central aim is the seeking after the attainment of the Truth, Immortality and Light. There is a Truth higher and deeper than the truth of the outer existence, there is a Light greater and higher than the Light of human understanding which comes by extraordinary and transhuman sight, hearing. There is an Immortality towards which the human soul has to rise. We have to find our way to that and get into touch with that Truth and Immortality. We have to be newborn into the truth, to grow in it, to ascend in spirit into the World of Truth and live in it. Such a realization alone is to pass from mortality to Immortality, to unite with the supreme Godhead.
Here is the second doctrine of the Mystics: There is an inferior truth of this world because it is mixed with much falsehood. There is another higher truth, the Home of Truth, The Truth, the Right, the Vast as taught in the mantrās. True knowledge there is termed ŗta-chit, Truth-Consciousness. And there are other worlds, but the highest is the World of Truth and Light. This is the World celebrated as the svar, the Great Heaven.
And this is the substance of the third Doctrine: In the world-journey our life is a battlefield of the devās and asurās; the Gods dev are the powers of Truth, Light and Immortality and the asurās, the powers of the opposing Darkness. These are Vŗtra, Vala, the Paņis, the Dasyus and their kings. We have to call in the aid of the Gods devāh to destroy these powers of Darkness who cover the Light. We have to invoke the Gods devāh in the inner sacrifice by the voice potent with the power of the mantra. To them offering of whatever is ours is made; receiving all that is given by them in return, we shall be enabled and competent to ascend the path towards of the goal of all round perfection and bliss.
Finally, this is the supreme secret of the vedic rişhis: At the summit of all the mystic teaching is ‘The One Reality’, ‘That One’ which later became the central goal of the rişhis of the Upanishads, taught with explanation in detail.