The supreme Shastra of the integral Yoga is the eternal Veda secret in the heart of every thinking and living being. The lotus of the eternal knowledge and the eternal perfection is a bud closed and folded up within us. It opens swiftly or gradually, petal by petal, through successive realisations, once the mind of man begins to turn towards the Eternal, once his heart, no longer compressed and confined by attachment to finite appearances, becomes enamoured, in whatever degree, of the Infinite. All life, all thought, all energising of the faculties, all experiences passive or active, become thenceforward so many shocks which disintegrate the teguments of the soul and remove the obstacles to the inevitable efflorescence. He who chooses the Infinite has been chosen by the Infinite. He has received the divine touch without which there is no awakening, no opening of the spirit; but once it is received, attainment is sure, whether conquered swiftly in the course of one human life or pursued patiently through many stadia of the cycle of existence in the manifested universe. Nothing can be taught to the mind which is not already concealed as potential knowledge in the unfolding soul of the creature. So also all perfection of which the outer man is capable, is only a realising of the eternal perfection of the Spirit within him. We know the Divine and become the Divine, because we are That already in our secret nature. All teaching is a revealing, all becoming is an unfolding. Self-attainment is the secret; self-knowledge and an increasing consciousness are the means and the process.
The usual agency of this revealing is the Word, the thing heard (sruta). The Word may come to us from within; it may come to us from without. But in either case, it is only an agency for setting the hidden knowledge to work. The word within may be the utterance of the inmost soul in us which is always open to the Divine; or it may be the word of the secret and universal Teacher who is seated in the hearts of all. There are rare cases in which none other is needed, for all the rest of the Yoga is an unfolding under that constant touch and guidance; the lotus of the knowledge discloses itself from within by the power of irradiating effulgence which proceeds from the Dweller in the lotus of the heart. Great indeed, but few are those to whom self- knowledge from within is thus sufficient and who do not need to pass under the dominant influence of a written book or a living teacher.
Ordinarily, the Word from without, representative of the Divine, is needed as an aid in the work of self-unfolding; and it may be either a word from the past or the more powerful word of the living Guru. In some cases this representative word is only taken as a sort of excuse for the inner power to awaken and manifest; it is, as it were, a concession of the omnipotent and omniscient Divine to the generality of a law that governs Nature. Thus it is said in the Upanishads of Krishna, son of Devaki, that he received a word of the Rishi Ghora and had the knowledge. So Ramakrishna, having attained by his own internal effort the central illumination, accepted several teachers in the different paths of Yoga, but always showed in the manner and swiftness of his realisation that this acceptance was a concession to the general rule by which effective knowledge must be received as by a disciple from a Guru.
But usually the representative influence occupies a much larger place in the life of the sadhaka. If the Yoga is guided by a received written Shastra, – some Word from the past which embodies the experience of former Yogins, – it may be practised either by personal effort alone or with the aid of a Guru. The spiritual knowledge is then gained through meditation on the truths that are taught and it is made living and conscious by their realisation in the personal experience; the Yoga proceeds by the results of prescribed methods taught in a Scripture or a tradition and reinforced and illumined by the instructions of the Master. This is a narrower practice, but safe and effective within its limits, because it follows a well-beaten track to a long familiar goal.
For the sadhaka of the integral Yoga it is necessary to remember that no written Shastra, however great its authority or however large its spirit, can be more than a partial expression of the eternal Knowledge. He will use, but never bind himself even by the greatest Scripture. Where the Scripture is profound, wide, catholic, it may exercise upon him an influence for the highest good and of incalculable importance. It may be associated in his experience with his awakening to crowning verities and his realisation of the highest experiences. His Yoga may be governed for a long time by one Scripture or by several successively, – if it is in the line of the great Hindu tradition, by the Gita, for example, the Upanishads, the Veda. Or it may be a good part of his development to include in its material a richly varied experience of the truths of many Scriptures and make the future opulent with all that is best in the past. But in the end he must take his station, or better still, if he can, always and from the beginning he must live in his own soul beyond the limitations of the word that he uses. The Gita itself thus declares that the Yogin in his progress must pass beyond the written Truth, beyond all that he has heard and all that he has yet to hear. For he is not the sadhaka of a book or of many books; he is a sadhaka of the Infinite.
Sri Aurobindo – The Synthesis of Yoga (Part 1, Ch 1, pp47-49)