Why is Rudra called Om? It is said because the breath (prana) has to be drawn upwards in pronouncing Omkar. Next, why is it named Pranava? Because it is used (pronounced) to pay obeisance to Rik, Yaju, Sama, Atharvangiras and Brahmins. That is why it is named 'Pranav'. Next, why is it called All Pervading (Sarvavyapi)? Because by mere recitation, it makes the aspirant Omnipresent. Like the oil in the oil-seed, pervading through all this, it, the peaceful Om, remains mingled and inter-mingled together. Next, why is it infinite? Because the mere recitation of it, makes the reciter feel neither beginning, nor end, or up and down, nor across. Next, why is it named Tara? The mere recitation of it enables one to transcend the great four of the trans migratory life consisting of conception, birth, old age and death. Next, why is it called Sukushma? Because, be mere recitation, the aspirant becomes very minute, dwelling in all the bodies. Next, why is it named Sukla? Because, by its recitation, one depresses and exhausts (his passions). Next, why is it Vaidyuta? Because a mere recitation of it, illuminates his whole body which is in great darkness. Next, why is it called the Supreme Brahman? The mere recitation of it makes him great. Next, why is He one? Because He alone uplifts all the worlds, always creates, preserves and destroys them. Next, why is He called one Rudra? (In reply to this a mantra is quoted). “Rudra alone exists and there is no second. He rules over all these worlds, possessed of creative and preservative powers. Having created the whole universe, He protects it. At the end, He destroys the same. O men, He remains inwards.” Therefore, He is called only one Rudra. Next, why is He called Isana? Because He rules over all the worlds, possessed of all supreme energies of power and rulership. (To support this a hymn is quoted here). “We approach you, O Mighty One, with salutations, like the calves before mulching. O Light, You are the ruler of the movable as well as of immovable ones, You are the light of the heaven.” Hence Isana. Next, why is He called Bhagavan (Lord)? Because He sees all things (directly) and also causes one to see the knowledge of Atman and leads one to Yoga. Next, why is He called Mahesvara? Because he devours all the worlds. He always creates, preserves and destroys them. Next, why is He called Mahadeva? Having given up all activities, He shines in His great glory of Atma-jnana-yoga. Hence Mahadeva. Thus is the mystery of Rudra.