AUM (OM)

About OM or AUM :

Talking about OM, one wonders why every mantra begins usually with OM. Why is OM known as a symbol of the Lord, and sometimes Lord Himself depicted as AUM.

AUM is made up of 3 letters: A, U and M (अ उ म )
Why is Lord AUM ?
Because Lord is अ, because Lord is उ and because Lord is म
Why is Lord अ (A) ?
अ in Sanskrit indicates negation. Like, Jnana * Ajnana, Vidya * Avidya, etc.,;
to indicate a 'NOT'; to negate something; to say that, 'this is not' jnana, 'this is not' vidya.
Then, what does अ indicate here ?
that Lord is NOT !
What is Lord Not !
Lord is Not this, He is Not that, 'nEti, nEti'
He is not the visible world of water, soil, and fire. He is not the invisible world of space and sound. He is neither 'sthoola jagat' nor 'sookshma jagat'.
He is neither concrete, nor abstract.
He is not anything that our eyes, ears, and all our senses can 'sense'.
He is not anything that human mind, intellect and ego can perceive.
He is above all these, He is above everything.
Hence, he is अ (A).
{Instead of telling 'What is God', OM says 'What is Not God' !
Why is this ? This is the way to explain things that human mind cant perceive. If somebody knows how a cow looks like, the person who is explaining about a buffalo can try to compare cow and buffalo; because he can relate a cow and a buffalo.
But, about Lord, one cannot compare anything with.
The easiest way, Veda found to explain, what God is, was by explaining what He is Not.}
Why is He अ (A) in this manner ?
Because He is उ (U).
What is उ ?
उ is the short form for Uttama (better), Unnata (higher), Upa-Upari (higher and nearer)
Lord is higher, better than anything else in this universe.
He is higher than what humans can apprehend. He is better than the best.
He makes us go higher and makes us better.
He cannot be understood by us. Nobody can comprehend, grasp anything about the Lord completely. He is absolutely unreachable by us !
Thus, He is उ.
Hmm, so, if He cannot be known, why should anybody try to know Him.
Why should anybody have anxiousness to reach Him ?
Should one stop Saadhana ?
No ! He is also म (M).
म is short form of maana, meaning knowledge, jnana. Maanam Jnaanam.
He is knowledge. He can be known !
These are two opposite points. He cannot be known says उ, but He can be known says म.
Yes, He is both.
He cannot be known completely.
To know, that He cannot be known completely, implies that He can be known !
We, at least, came to know that, He cannot be known completely.
Isn't this knowing something about Him ?
He is Jnana-saagar, ocean of knowledge.
We have come here to gain knowledge.
We cannot completely know the ocean.
If we come with a spoon, we will get the water from the ocean that fills up the spoon.
If we come with a tumbler, we will get water as much as can be filled in the tumbler.
We get a bucket, we fill the bucket.
All our vessels have been filled ! The ocean didn't dry up. But, we got an idea of what the ocean is. We have known something about Him.
Hence, He is म (M)
He is अ उ म (AUM).
(Excerpts from Bannanje Govindacharya's lectures)