Sri Aurobindo translates Prashna Upanishad, Fifth Question, Verses 1-4: “Then the Shaibya Satyakama asked him: ‘Lord, he among men that meditate unto death on OM the syllable, which of the worlds doth he conquer by its puissance?’ To him answered the Rishi Pippalada: ‘This imperishable Word that is OM, O Satyakama, is the Higher Brahman and also the Lower. Therefore the wise man by making his home in the Word, winneth to one of these. If he meditate on the one letter of OM the syllable, by that enlightened he attaineth swiftly in the material universe, and the hymns of the Rig-veda escort him to the world of men: there endowed with askesis and faith and holiness he experienceth majesty. Now if by the two letters of the syllable he in the mind attaineth, to the skies he is exalted and the hymns of the Yajur escort him to the Lunar World. In the heavens of the Moon he feeleth his soul’s majesty: then once more he returneth.”
The Prashna Upanishad is one of several Upanishads that address the syllable OM and its significance. The focus here is on the relationship of OM to the various planes of existence and to the Supreme. Recitation of the syllable itself is considered highly effective to bring about a state of calm peaceful contemplation. The vibratory pattern aligns with the sound of the universe and removes conflicting vibrations that distort the concentration. The syllable is traditionally said to be made up of the combined sounds of A, U, M. There is considerable symbolism and meaning attached to each of these letters, and the combination of them as one complete syllable.
The Upanishad is not, however, implying that, for instance, concentrating on “A” leads to “the world of men” and concentrating on “U” or “AU” leads to the “lunar world”. It is important to distinguish between the symbol and the concentration on the reality behind it. The Upanishad is defining the process of focused concentration on one particular aspect of the universal creation related to each of the symbolic letters. If a man focuses on the material creation, he attains the results in that field and progresses on the plane of Matter. If a man focuses on the vital world, he achieves results in that sphere and when that energy is exhausted, returns to the human birth to continue his growth and progress.
The symbolism of the Upanishads describe, sometimes using varying terminology, the successive planes of matter, life, mind and supermind, and beyond all of them, the Eternal, the Supreme. Matter is the plane signified by “A”. Life is the plane signified by “U”. In the Taittiriya Upanishad, these are designated as “bhur” and “bhuvar”. Each plane has its own conditions, its own energies and its own type of results. A concentration on any one plane is insufficient for a complete knowledge of Brahman, which encompasses both the Unmanifest and the Manifest. This is referred to here as the “Higher” and the “Lower” Brahman. It is only through an integral process that brings together the entire manifestation and what is beyond the manifestation, that the complete realisation of the meaning of OM can be achieved.
Sri Aurobindo, The Upanishads, Prashna Upanishad, pp.297-315