From the book "The crown of life", written by Sant Kirpal Singh

It is in the context of this problem that Surat Shabd Yoga, or the yoga of the celestial Sound Current, assumes its unique importance. Those who have mastered this yoga teach that the Absolute, though free of attributes in Its primal state, projects itself into form and assumes two primary attributes: Light and Sound. It is no mere accident, they point out, that in the revelatory literature of all major religions there are frequent references to the "Word" which occupies a central position in their pattern. In the Gospels we have:

In the beginning was the Word and the Word was with God and the Word was God.
ST. JOHN

In ancient Indian scriptures we read repeatedly of Aum, the sacred Word pervading the three realms of bhur, bhuva and swah (i.e., the physical, astral and causal). Again, Nanak says:

The earth and sky are of naught, but Shabd (Word).
From Shabd alone the light was born,
From Shabd alone creation came,
Shabd is the essential core in all.
Shabd is the directive agent of God, the cause of all creation.
PRABHATI

The Muslim Sufis declare:
Creation came into being from Saut (Sound or Word) and from Saut spread all light.
SHAMAS TABREZ

The Great Name is the very essence and life of all names and forms.
Its manifest form sustains creation;
It is the great ocean of which we are merely the waves,
He alone can comprehend this who has mastered our discipline.
ABDUL RAZAQ KASHI

Moses heard the commandments of God amidst thunder and flame, while in Zoroastrian and Taoist thought alike there are references to the "Creative Verbum," the "Divine Light," and to the "Wordless Word," the silent Word.

Some learned scholars and theologians in subsequent times, because of their own limited experience, have interpreted these descriptions as metaphoric references to intuitive or intellectual enlightenment. On closer examination such a position will be found to be untenable. The terms "Word" or Logos as used by the Greeks, Hebrews and Europeans, may be distorted to mean "reason" or "order," and "light," may even be made to mean no more than mental illumination, but their equivalents in other religious literature – nad, udgit, akash-bani, shabd, naam, saut, bang-i-Ilahi, nida-i-asmani, sraosha, tao, and jyoti, prakash, tajalli, nur-i-yazdani, etc., refuse to bear such a travesty of their original mystic meaning. What is more, some seers have stated their real connotation in such a way that there can be no scope for equivocation or room for doubt that what is involved is not figurative expression of ordinary mental experience, but transcendent inner perception.

Thus, in the Revelation of St. John we have:
His eyes were as a flame of fire … His voice as the sound of many waters… His countenance was as the sun shineth in his strength … And I heard a Voice from heaven, as the voice of many waters, and as the voice of a great thunder: and I heard the voice of harpers, harping with their harps.

While in the Upanishads we are told:
First the murmuring sounds resembling those of the waves of the ocean, the fall of rain and then running rivulets, after which the bhervi will be heard, intermingled with the sounds of bell and conch.
NAD BIND UPANISHAD

The Prophet Mohammed heard celestial music which gradually assumed the shape of Gabriel and formed itself into words; while Baha U’llah relates:
Myriads of mystic tongues find utterance in one speech, and myriads of His hidden mysteries are revealed in a single melody; yet alas, there is no ear to hear nor heart to understand!

Blind thine eyes, that thou mayest behold My Beauty, and stop thine ears that thou mayest hearken unto the sweet melody of My Voice.

These references to Light and Sound, say the Masters of the Surat Shabd Yoga, are not figurative but literal, referring not to the outer illuminations or sounds of this world, but to inner transcendent ones. They teach that the transcendent Sound and Light are the primal manifestations of God when He projects Himself into creation. In His Nameless state He is neither light nor darkness, neither sound nor silence, but when He assumes shape and form, Light and Sound emerge as His primary attributes.

This spirit force, Word, Naam, Kalma or God-in-action, is responsible for all that is, and the physical universes that we know are not the only ones that It has created. It has brought into being myriad regions and myriad creations over and above the physical. Indeed the whole is a grand unfathomable illimitable pattern in which the Positive pole (Sach Khand or Sat Lok) is a plane of pure, unalloyed spirit, while the Negative pole (Pind) is of gross physical matter with which we in this world are familiar. In between are countless regions which those who have journeyed from one end to the other often divide into three distinct planes in accordance with the balance of Positive – spiritual and Negative-material forces in each plane.

The Masters teach that the one constant principle that links all these planes from pure spirit to gross matter is the principle of the flaming sound or the sounding flame. The Word or Shabd as it descends downward assumes a varying density of spirituo-material forces. Mystics speak of the purple light and the light of the noonday or setting sun, and refer to the sounds of flutes, harps, violins, conches, thunder, bells, running water, etc., but though manifesting differently at different levels the Shabd yet remains constant in Itself.

As a river springing from the snowy peak of a towering mountain flows toward the sea, it undergoes many changes of setting, shape, motion and appearance, and yet its waters remain the same.

If one could discover this audible life-stream within oneself, if one could discover its lower reaches, one could use it as a pathway leading inevitably to its source. The currents might at certain points enter gorges and rapids, but nevertheless they are the surest way on the upward journey. Be a range howsoever unscalable, the waters will have cut a pass and carved a passage, and he who will avail himself of their guidance would never fail to find a way. And since this Naam or Word-current springs from the Anaam or the Wordless, he who holds firmly to It will inevitably reach the starting point, transcending plane after plane of varying relativity until he arrives at the very source of name and form; thence to merge into That which has no name or form.