The syllable Om is made up of 3 aksharas (letters)- A, U and M.  All 3 of them are jointly blended and uttered. The combination or merging of the sounds A (guttural–from the vibration in the throat area as breath is expelled) and the U by curving the lips (labial) produce the sound “O”. The consonant “M” is produced by closing the lips while still vibrating. That completes the sound production of the syllable Om.  

This syllable Om is all pervasive, s’reshtam  (most preferred of all) of all the speeches (Vaak) categorically declares the Upanishads. We as humans produce a lot of sounds. Why is this special? Why is this eulogized?  In fact, it is not just eulogy but exaltation as the Supreme Self as declared in the sacred scriptures as brought out earlier. All major religions give this syllable a special, positive status on top, at the highest pedestal, above everything.  Mantras are formed out of the Sanskrit vowels and consonants. Mantras are said to be protecting our minds from the effects of evil. So what makes the Om and the mantras special and different from the normal sounds we make in our day to day lives? 

For one to know and understand or investigate, one has to believe and have faith in the scriptures. One must have faith in the revelations and utterances of Ṛṣis/Seers who have experienced Brahman, the Supreme. They have passed on their knowledge to the disciples and it is in the forms of Vedas and Upanishads. This scribe has his belief in the scriptures to begin with while trying to address this question. With that firm belief, one has to follow the prescribed procedures with patience to embrace the end result which is to experience that all are Brahman. Upanishads promote meditation on Om or on Om as various Divine Forms. The poojas, the chanting, the mantras, the offerings in the Fire (Havan), and the rituals sacrificing herbs and grains in the Fire all have one common aim viz., to give up what we have unnecessarily acquired to reach the final stage when we are finally left with just us, Brahman, permeating everything, us in everything and therefore not wanting anything. 

The breath from inside the stomach vibrates the vocal chords in the throat region and produce the sound “A” which when merged with the labial sound “U” produces the sound “O”. When the consonant “M” is produced by closing the lips, the vibration and the breath is retained and not given out. The sound produced is internalized and is “kumbham” (retained breath and not given out). This verbal expression is equivalent to the visible vyavahārika (Transactional Brahman). The three aksharas are united from the origin (bottom of the neck, throat area) to the end (lips). It is within this area all sounds and aksharas are produced with the tongue in different positions inside the mouth. This speech (Vaak) function is in the face through the mouth. Vaak (Speech) is considered to be sacred Agni (Fire) in the scriptures (11** PURUSHA SUKTAM). 

The sounds produced by humans is from the flesh-body. However, scriptures give a special status for this Om sound and the mantras that we humans produce. Everything here is Om says Mandukya Upanishad (6**).  What is its relationship to potential Divine power and the effect of mantras which are described to be protecting the minds is the question.  

In the spiritual parlor, there is a definite relationship between the sound (of an alphabet) and its meaning. Learned call it “sanketam” (a condition, a stipulation) and “sannikarṣam” (relation to, connection) with – Divinity.  This relationship is said to be established by Is’waran (the Supreme Governing Lord) as “Iswara Āgjnya” (Command of the Lord). And it cannot be changed is the emphasis in the Sastras (injunctions and codes of conduct). 

So, mantras in the Vedas and prayers made out of aksharas (alphabets) that are revealed to us by the seers are potent Divine Blessings for the uplift of one self. These mantras, revealed to Seers are verbalized by them with their flesh-body organs for the benefit of mankind. That is why they are called mantras, the meaning being “protects the mind”; protects it from the penetration of evils (body-sense orientations). The seers of these mantras are known as Mantra Dṛuṣtas. The Divine power of the mantras manifest in them due to their strong, unshakable belief and after intense unrelenting tapas (meditation) for years. It is a natural consequence and outflow of their tapas.  

A normal worldly human being has two minds: (1) that with one’s likes and dislikes due to one’s delusion and conditioned thinking that one is a body and (2) that of the Divine part of him which is not conditioned and all pervading.  The presence of the second Divine part in humans is mentioned to us in the Upanishads and by Sri Krishna in Bhagawad Gita where He states “Aham Vaiswanaro Bhūtwa Praṇinām dehamās’ritaha” ( I become Vis’wa nara  Agni and am resident in the body of all beings) (12 **BG, 15; 14 *). Vais’wanara Agni is Is’waran Himself says Brahma Sutram (13 ** BS First Adhyasa, Second Pādam, Sut 24-32). 

The flesh-body mantra sound utterances of the human must have a sympathetic vibration in the Divine part resulting in a thought-elevation of his mind. In a finely tuned stringed instrument, violin, when one vibrates the note say “D”, the open string D produces the sympathetic vibration. This phenomenon is what, I think, elevates the person and that is why those indulging in poojas, chanting, havans etc. feel good and their satwic nature increases. The physical process involved in the pooja and havan is meditation if one puts one’s thought and actions on the Divine Beings with the utterances of the mantra words. It is involving oneself in Thought, Word and Deed. Sri Krishna is said to have given Arjuna a Divine Eye to show His All-Pervasive Form. Similarly, there should exist  in us a Divine Ear for Divine Vibrations. It is to attain this Divine Eye and Divine Ear that seekers meditate to experience Divinity. Thus, it is erroneous to reject mantras, poojas and rituals as archaic. I do agree that the beginning of Creation itself is archaic and not modern and fancy. It is important that the God Thought and corresponding activities as much as possible in whichever way one can do that. No wonder S’ankara in His Bhaṣhyam states that God is pleased when one utters Om just like a person is pleased by the name he likes best (14 ** Chandogya Upanishad, 1-1-1 ). That is why Narāyaṇa is said to be “Stuti Priya” (one who likes His Name to be chanted). No wonder Swami has stated repeatedly that Nāmasmaraṇam (repeated chanting of God’s Name) is the medicine for the ills of this Kali Yuga. This Nāmasmaraṇam is the prescription given to us in the Kali Yuga by Vasishta Brahma Ṛṣi too in the Viṣṇu Purāṇam (15** Vishnu Puranam Namasmaranam ). 

S’ankara Bhasyam to Chandogya Upanishad text explains the role of Om and Agni.  The text says that Praṇavam (Om) is Udgītha and Udgītha is Praṇavam (14**). Udgītha is a meditation of a Divine Form (and equated to Om) which will be described later. In a subsequent text, Chandogya says that the Breath (the vital Force) in the mouth (Vaak, Speech) should be meditated upon as  Udgītha for it moves along pronouncing Om (16 ** Chandogya Upanishad, 1-5-3*). This movement pronouncing Om enables exciting functioning of speech and various parts of the body says S’ankara. One should note that here Breath refers to the Vital Force in us and not the air that we breath and the breathing of air to our lungs is due to the Breath, the Vital Force. Breath in the Mouth is Speech and Agni. Breath and Speech are the Divine parts in us, humans. And they keep uttering Om (which we, normal humans do not hear and which possibly is heard only by the Seers with a subtler Divine Sound) as approval and permission as we indulge in rituals, prayers, reading scriptures and doing meditation. That is how we are Blessed and get mental uplift as we practice prayer of any form and meditation. Divinity keeps pronouncing Om (Vital Force) as we perform. For those who have perfected the process and achieved yogic nature and/or in tune with Divinity, these powers are manifested on its own because it is the nature of Divinity. One should not aspire for yogic powers which are just ornaments, but only to the Supreme Is’waran who possess them. The focus should be on the One who has all, but not on the parts or derived benefits. When we multiply our mundane, worldly activities we don’t use that excitement or pronouncing of Om by Breath, the Vital Force.  We deviate thus. We ignore and waste that Energy that sustains our activities. We misuse the energy meant for prayer and elevation to indulge in pursuits of sense and body orientation. We go up or go down the ladder depending upon how we use our Energy and time; it is up to us to chalk our future (in a sense because Prārabdha karma and unseen Divine Hand play a role too to influence us and implement karmas that we have to go through (prārabhdam)). 

Patañjali Mahaṛṣi’s Yoga Sastra defines clearly the syllable Om. He says Om (Praṇavam) is Is’waran’s Speech or Himself (Tasya Vāchaka Praṇavaha) (17 ** Patañjali Yoga Sūtram, Samādhi Pādam, Sūtram 27.). Praṇavam is defined as “prakarṣena tuyate anena iti” which means Praṇavam is praised and worshipped in many ways. Thus, Om attains the highest status in the Transactional World. That is why S’ankara calls Om as the next and closest to Brahman and Pras’na Upanishad says it is both visible and invisible Brahman. 

More the worship and more the ways to worship, greater the Divine thoughts in our minds. This, most importantly, also is a barrier to the evil penetrating the mind and thus rituals and prayers are speed-breakers to our craving minds lured by the varieties of the modern world. However, our scientific mind seems to negate and discard poojas, prayers and havans as redundant, unproductive and that only meditation matters. Yet we are unable to get that concentration and ekagrata (one pointedness) that is a first requirement to make any headway towards success in meditation. We do not realize and understand that the rituals and prayers are stepping stones for that and that the Ṛṣis of ancient times did exactly that. Yet we want to be that Brahman (which Ṛṣis attained after sustained efforts and guidance for years) without much proper effort or progressive steps or input and discarding the methods of Ṛṣis. We seem to get deluded into thinking that we are all Brahman because Adi Sankara has said that we are all Brahman and the world is a myth. We also seem to think that Faith in a Sad guru or a Divine Name and Form is sufficient. While Faith is a necessary condition, it is not the only condition. To my knowledge Adi Sankara has never criticized or degraded rituals and prayer. Humans are born to act and to clear the prārabhda karmas one has to act. Humans are always involved in actions and when the actions are geared towards God, it sanctifies the time spent and prepares one for concentration and contemplation. These rituals themselves are a part of the meditative process to enhance concentration.  These rituals become a stepping stone for meditation and realizing one’s Self. It is better if human acts are oriented towards prayer, rituals and help to others. The primary purpose of Service to others is to purify oneself. That is why Swami in His Infinite Wisdom has put seva, bhajans, pooja, havan and rituals along with scriptural studies as necessary steps to mankind. Just like Swami, Sri Krishna has also clearly stated in the Bhagawad Gita that Yagyam (Prayer, pooja, Havan prayer), danam ( giving wealth or time or help to others ie., service) and tapas (meditation on the Divine) are all always Omkāra ( 8 **BG  17:24 *.  “Yajyam, danam, tapah Kriyaa satatam Om iti”).  Sri Ramana Mahaṛṣi has emphasized that one has to know oneself first and then he can be of greater service to clear the delusion of humanity. All the satwic acts are, therefore, only intermediary steps towards the ultimate goal. They all are the means and not the end. One should encourage all such acts and NOT discourage and look down upon some as meaningless and “does not make sense”. Swami Himself had Discoursed that acts like “pouring” ghee (clarified butter) into havan is NOT a waste compared to gobbling tons of buttered sweets.  

The effect and the power of the mantras is clearly mentioned in Bṛahadāraṇyaka Upanishad. It thunders “Should one sprinkle it (here “it” refers to pooja/prayer water or grains or anything made for a yagjna with prayer and mantras to produce an effect) even on a dry stump, branches would grow and leaves sprout” (18** Bṛahadāraṇyaka Upanishad, Chapter 6, 3.7).  An incident like this has actually happened about 350 years ago. It is said that Sri Raghavendra Swami (of Mantrālayam) sprinkled water uttering mantras on a dried-up twig and in a week’s time, the about-to-die, dried-up twig sprouted young leaves in its stem (19** Sri Raghavendra Swami, Mantralayam Book).  That is due to the mantras and the natural flow of power of the Ṛṣi. Swami’s, Sri Satya Sai Baba’s, numerous powers are also similar in that it is a natural flow from His Divine Self since very young in His Physical age. Swami’s aim was simple; to show the enquiring minds that there is a Supreme Power above our normal sense-perception and for our own good and the good of others, there is a need to worship, pray and Realize the Divinity in us. There are many instances of powers of mantras in Puranas and in karma kāṇḍam part of the Vedas. Instances of the necessity of correct utterances and pronunciation of the mantras with its ups and downs and its effects are also present in the spiritual literature. While there are many mantras in the Vedas for rituals to invoke favor from Gods, the Single Aksharam Mantram, Om, stands above all and pervades all and Om is always uttered along with other mantras. OM is the source of all the other mantras and Vedas as stem is the basis for many leaves on it says Chandogya Upanishad (9** Chandogya Upanishad, 2-23-3).  

Here is an interesting question and answer in the Pras’na Upanishad. The student Satyakama wants to know from his Guru Sage Pippalada what would be obtained if one meditates on Om till death. The answer brings out the effect of the components that make up the syllable Om. ‘ (20 ** Pras’no Upanishad, 5: 1 thro 7)

• Om is the Highest (Para) and the other (Apara) Brahman. So the knower attains one of the two Brahman state.
• If he meditates on “A” alone and is enlightened by “A”, then the Ṛc verses bring him back to the Earth endowed with penance, faith, righteousness and greatness. 
• If he meditates on “A and U” (dvimātreṇa) and is enlightened, then the Yajur verses take him to the sky (Antarikṣam), the Soma World for which Moon (manas, the mind) is the Deity and after enjoyment returns to the Earth.  
• If he meditates on the Supreme Purusha as the combined three aksharas (AUM and not as A,U and M), then the Sāma Verses take him to the Sun and he becomes part of the Sun and does not return to the Earth. He is in the Brahma world, the World of Poets^*. He arrives at this by means of the Omkara. * In prayer to Maha Ganapathi we chant “kavim Kavīnām” meaning poet of poets eulogizing Lord Ganesha as the First (Jyeṣta Rājam) and the Primary Poet. No wonder we call Him Praṇava Swarūpam. Note that the term “Kavi” does not really mean a poet used in the ordinary sense of the word poet viz., one who writes verses in a language (like the great poets Wordsworth or Keats), but to Seers who are Vaak (Speech) Themselves. Seers’ Speeches are Divine Utterances that influences Spiritual Thoughts just like the words of great poets that invoke Nature and the world influences our emotions. Nature and the world too are Divine but only with a proper perspective and Realization; otherwise they become objects of enjoyment for the senses. 
• If he meditates employing the three aksharas separately as A, U and M and only joined but not blended into one syllable, then he is mortal. 

• “A” leads to glory among men and is external. “U” leads to the mind level powers and enjoyment and is only intermediary and incomplete. “M” internalizes and when blended with A and U lands one in the Brahma world and one is free from fear of death.  The Upanishad gives a beautiful simile here. It states that “as a snake is freed from its skin”, so is the Om meditator freed from evil. Swami has guided Dr. Goel to the Brahman state and his experiences and journey are written in the book “Third Eye and Kundalini” (21** Dr. B.S. Goel, “Third Eye and Kundalini”, Third Eye Foundation of India, 33, New    Colony, Kurukṣetra, Haryana, India 132118.). In that book, Dr. Goel has mentioned that he experienced that he had a darker outer skin and a bright Golden inner skin. When the outer skin was discarded, the inner bright, illuminating skin made its appearance. Just like the snake, we need to discard the dark outer skin that pushes us towards sense enjoyment and Realize the Golden Inner skin. That is why a snake is associated with senses and is considered a factor that pulls one down in the ladder to climb towards Divinity (cf. Snakes and Ladder game).  Once the snake (Jiva) sloughs the outer skin, the Jīvā is free from bondage and liberated. The comparison of Jīvā to a snake is beautiful, is it not? It is all the more enlightening and creates exuberance in us when we know that Swami, guiding Dr. Goel to Divinity (in absentia), has made him realize this Reality.  
• Dr. Goel has also mentioned in his book that Swami has elevated several people to higher levels of spirituality. So, the 3 aksharas have to be blended in uttering and meditated upon. That is why it is a single syllable. The three verses Ṛc, Yajus and Sāman takes one to glory in this, intermediary and in the World of Poets. That is why Om is stated to be the Vedas and represent Vedas. The Vedas are there for us humans to adopt and follow that pattern of life- a Vedic life which regretfully we do not follow and some of us scorn at it too. What a pity.

In Bhagawad Gita, Sri Krishna says that among aksharas He is “A” and among Vedas He is Sāma Vedam (22 **Bhagawad Gīta, Chapter 10, S’lokas 22 and 33). This is not to be interpreted as that he is the Ṛc Verse only bringing us back to the world with righteousness and glory.  What Sri Krishna meant was that He was the first Vak (expression) -speech as the aksharam “A”, the beginning and the creator of the sound from which Vedas, Speech and  all emanated. He states that He is the very First Expression of perturbance from an unperturbed state; from Avyaktam to Vyaktam. He declares that He is Is’wara.  By saying that He is Sāma among the Vedas, He has told us of His quality of samatwam (equanimity) and that He is the Poet, Om, Praṇavam and the highest in the transactional world. Besides Sāma Veda is mainly Ṛc mantras in a melody and sung. That is why if one merges with Sri Krishna, one would be in the highest position and the Sāma Verses would take one to Him as explained in the effect of the blended sound AUM (Om) and as said in the Upanishads (20). That is why Sri Krishna says in the Bhagawad Gita, that He is Ṛc, Yajus and Sāma Vedas and Omkāra (23 **Bhagawad Gīta, Chapter 9, S’loka 17) “Among Vedas, I am Sama Vedam” said Sri Krishna (22) to emphasize that He is the Noblest among Vedas and is beyond Mind (the  World of Moon—Ṛc and Yajus) and the world of flesh bodied world of humans ( Ṛc Veda ; Sound “A”) and that He pervades all the worlds and above them as that One syllable Om ( “Asmekam aksharam”) (24 **Bhagawad Gīta, Chapter 10, S’loka 25). One should note that Divine Being Krishna has identified Himself with the sound Om. It should mean that Divinity is not merely a sound but the Energy and power of Creation, Sustenance and Assimilation. All the above seem to be associated and intricately blended with the sound Om. Om is not just a sound. It is Divine Utterance.