The Hindu philosophy behind this is the premise that before existence and beyond existence is only One reality, Brahma, and the first manifestation of Brahma expressed as Om. For this reason, Om is considered as a foundational idea and reminder, and thus is prefixed and suffixed to all Hindu
prayers. Om is also considered the most sacred mantra and the most commonly used.
Om ( ॐ; in Devanagari as ओं oṁ
[õː], औं auṃ
[ə̃ũ], or ओ३म् om
[õːm]) is a mantra and mystical sound of Hindu origin (geographically India and Nepal), sacred and important in various Dharmic religions such as Hinduism, Buddhism, Sikhism and Jainism. As to its precise graphic form, the Vedic or Indian om is what most Westerners are used to.
It is placed at the beginning of most Hindu texts as a sacred incantation to be intoned at the beginning and
end of a reading of the Vedas or prior to any prayer or mantra. It is used at the end of the invocation to the god being sacrificed to (anuvakya) as an invitation to and for the latter to partake of.
Hindus believe that as creation began, the divine, all-encompassing consciousness took the form of the first and original vibration manifesting as sound "OM".
The vibration of "OM" symbolises the manifestation of God in form ("sāguna brahman"). "OM" is the reflection of the absolute reality, it is said to be "Adi Anadi", without beginning or the end and embracing all that exists.
The mantra "OM" is the name of God, the vibration of the Supreme. When taken letter by letter, A-U-M
represents the divine energy (Shakti) united in its three elementary aspects: Bhrahma Shakti (creation), Vishnu Shakti (preservation) and Shiva Shakti (liberation, and/or destruction)
"Om" The sound of the universe. It's the first, original vibration, representing the birth, death and re-birth process.
For thousands of years, people have used this mantra to expand their awareness of the divine.
Chanting the sound OM brings us into harmonic resonance with the universe – this is a scientific fact! OM is said to vibrate at 432 Hertz, which is the natural musical pitch of the Universe, as opposed to 440 Hertz, which is the frequency of most modern music.
This is one word that anyone can feel comfortable using, no matter your spiritual inclinations. It is an incredibly soothing sound, especially when you allow the vibration to linger in your throat.
You can literally feel your body vibrate when you repeat this mantra for a little while...
For starters, you can focus on the silence from which "Om" originates and into which it dissipates. That will quickly give your mind something to focus on and help you enter and stay in meditation.
Source: Wikipedia;
The hidden power in humans, Paramhans Swami Maheshwarananda, Ibera Verlag;
Rituals and Mantras, Rules without meaning, Frits Staal
“Traditional American Indians are raised to respect the Christian Star and
the birth of the first Indian Spiritual Leader. He was a Star Person and Avatar.
His name was Jesus. He was a Hebrew, a Red Man. He received his education from
the wilderness. John the Baptist, Moses, and other excellent teachers that came
before Jesus provided an educational foundation with the Holistic Method.”
The year is almost finished ...
"Mantra" (Sanskrit मंत्र - «m.; also n. mantram» consists of the root man- "to think" and the suffix -tra, designating tools or instruments, hence a literal translation would be "instrument of thought") means a sacred utterance, numinous sound, or a syllable, word, phonemes, or group of words believed by some to have psychological and spiritual power. In other words "Mantra" has two parts: man, which is the root of the Sanskrit word for mind; and tra, which is the root of the word instrument. 
