OM Mantra itself is not a mere human invention, going long with particular cultures or groups. Rather, the OM Mantra (or AUM Mantra) is a symbol of deep realities that already exist.
The levels of gross (A), subtle (U), and causal (M), and the states of waking (A), dreaming (U), and deep sleep (M) are definitely there, regardless of the symbolism captured in the mantra when stated as AUM Mantra. It is these realities that are most useful in our spiritual practices. If the OM mantra is repeated just for the feeling, having no sense of meaning at all, the experience can be quite pleasant, calming, and balancing.
However, if one has a sense of the deeper meanings of the mantra, and different methods of using it, then the experience can be even richer and more revealing as one progress in yoga meditation. By experimenting with the various methods, one of them may emerge that feels mos personally in tune. The use of this mantra can be profound. At first, it is best to use the mantra gently and for short periods of time.
The insights from the OM mantra can be significant, and it is good to integrate the insights gradually with daily life.
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