सर्वस्य प्रणवो ह्यादिर्मध्यमन्तस्तथैव च ।
एवं हि प्रणवं ज्ञात्वा व्यश्नुते तदनन्तरम् ॥ २७ ॥sarvasya praṇavo hyādirmadhyamantastathaiva ca |
evaṃ hi praṇavaṃ jñātvā vyaśnute tadanantaram || 27 ||27. Aum is verily the beginning, middle and end of all. Knowing Aum as such, one, without doubt, attains immediately to that (the Supreme Reality).
Shankara Bhashya (commentary)
Aum 1 is the beginning, middle and end of all; that is, everything originates from Aum, is sustained by it and ultimately merges in it. As2 the magician, etc. (without undergoing any change in themselves) stand in relation to the illusory elephant, (the illusion of) snake-rope, the mirage and the dream, etc., so also is the sacred syllable Aum to the manifested manifold such as Ākāśa (ether), etc. The meaning is that he who knows thus, the Aum, Ātman, which, like the magician, etc., does not undergo any change, at3 once becomes unified with it.
Anandagiri Tika (glossary)
1 Aum—When a cause, etc., of the universe is sought, Aum is pointed out as such. This is in accordance with the Pariṇāmavāda.
2 As the magician, etc.—This is from the standpoint of the Vivartavāda. The magician, the rope, the desert, etc., appear as the elephant, the snake, the mirage, etc., without undergoing any change in themselves. Similarly Aum also, from the relative standpoint, appears to have become the entire manifested manifold without undergoing any change in itself. But from the standpoint of soundless Aum, there is no manifested manifold. It is not the cause of anything nor does it appear in any way other than itself. Aum is inferred as is a juggler (māyāvi) by those who see the fact of creation and explain it as Māyā. Therefore, the idea of the juggler is also an illusion and it lasts as long as we look upon the manifold as Māyā. It vanishes as soon as the Māyā or illusion disappears.
3 At once—Jñāna or knowledge is aone the cause of Mukti which does not depend upon anything else. The moment we know the real nature of Aum, we become unified with it.