Significance of Hari Om
Pujya Sri Mota has given the significance of the Mantra: “ HARI OM or HARI AUM “ at several places in his writings. Here too, in this Aarati-Bhajan, he has repeated: “ Om /Aum” in each stanza. There is a fine explanation of this. It may be added that the Mandukya Upanishad, which deals with these four states, though in a very compressed manner, states that the Mantra Om can be considered as a split up into the three elements, A, U, M. Of these A signifies the Jagrat State, U the Swapna and M the Sushupti, while the Om, taken as a single unity, stands for the “ Fourth “. The repeated counsel to meditate on the Om has no reference to setting up “vibrations” in the Subtle body but to raising the consciousness through the three stages into the Fourth.”short meanings of the terms: Jagrat (Waking), Swapna (Dreaming), Sushupti (Deep-sleep state), the Fourth (Turiya):” is that of sheer transcendence, the unmanifested consciousness of the Shanta Atman. It is the Goal and is best left in silence.
(Taken from Appendix C, note on the four states of consciousness—“The Yoga of the Bhagavat Gita “ by Sri Krishna Prem)