This section is from the book "Studies In Saiva-Siddhanta", by J. M. Nallasvami Pillai. Also available from Amazon: Studies In Saiva-Siddhanta.
* With reverence present your Hymn to-day to the mighty Rudra, the ruler of heroes, [and to the Maruts] those rapid and ardent deities with whom the gracious (Sivah) and opulent (Rudra) who derives his renown from himself, protects us from the sky." Sayana takes ' Sivah' as a substantive and interprets it as meaning Paramesvara ; and it seems strange that Muir should take it as an adjective.
He is 'antar ickchanti - beyond all thought (VIII. 61-3). His form as described in the Rig Veda is almost the same as the Image of later days. He is called the Kapardin, with 'spirally braided hair.' He is of Hiranya Rupam 'golden formed' and brilliant like the sun, and 'shining like gold' "Yah Sukra iva Suryo hiranyam iva ro chati" (I. 43-5).* And in Rig Veda X. 136-1 to 7, He is the Long haired being who sustains the fire, water and the two worlds; who is to the view the entire sky; and who is called this 'Light' He is wind clad (naked) and drinks Visha (water or poison) and a Muni is identified with Rudra in this aspect.
When we come to Yajur Veda, His supreme Majesty is fully developed, and He is expressly called Siva by name ' Siva nama si (Yaj. S. 3-63) and the famous mantra, the Panchakshara, is said to be placed in the very heart of the three
Vedas, (the name occurs in Tait. S. IV. 5, 1-41 ' namah sambave cha mayobave cha namah Sankarya cha mayaskaraya cha namah sivaya cha Sivataraya cha"). And the famous Satarudriyam which is praised in the Upanishats and in the Mahabharat forms also a central portion of this central Veda. And this is a description of God as the all, the all in all, and transcending all, 'Visvadevo, Visvasvarupo, Visvadhiko'; and any body can see that the famous passage in the Gita in chapters 10 and 11 merely parodies this other passage. These two chapters are respectively called Vibhuti Vistara Yoga and Visvarupa Sandarsana Yoga which is exactly the charactor of the Satarudriya. The Yogi who has reached the highest state "Sees all in God and God in all." In the Satarudriya and in the whole Veda, Rudra is called Siva, Sankara Sambhu, Isana, Is a, Bhagavan, Bhava, Sarva, Ugra, Soma, Pasupati, Nilagriva, Girisa, Mahadeva and Mahesvara. And the most famous mantra 'Ekam Eva Rudronadvitiyaya taste' whose very existence in the Vedas and Upanishats scholars doubted at one time, occurs in the Yajur Samhita (Tait). in 1 Canto, 8 Prasna, 6 Anuvaka, 1 Pafichasat and this very mantra is repeated in our Upanishat, (III 2,) and if the Upanishats did not precede the Vedas, it will be seen how this mantra is the original of the other famous Upanishat mantra, "Ekamevadvitlyam Brahma." In fact, we doubt if the word 'Brahma' occurs even once in the Rig-Veda as meaning God, and in the Yajur as meaning the Supreme Being. And Prof. Max Muller is no doubt correct in drawing attention to the fact that the conception of a mere Impersonal Self may be posterior to the conception of God as Siva, Rudra and Agni. And the texts we have above quoted will for once prove the danger of surmises as to the date of an Upanishat for the sole reason that it uses the words Siva or Isa or Isana and Rudra.
* Note how often the Supreme is called the Golden-coloured, and Sunlike in the Upanishats.
In the days of the Veda and the Upanishats, these names Rudra, Siva, Sambhu, Mahadeva, Isa, Isana, Hara and Vishnu only meant the same as Deva or Brahman or Atman or Paramatman, and they had no prejudice against the use of the former set of words, as some sectarians of to-day would seem to have. In the Gita itself, the words Isvara, Isa, Mahesvara and Mahadeva and Paramesvara are freely used, and Siva is used in the Uttara Gita, though the modern day Vaishnava exhibits the greatest prejudice towards these names.
One word about the different aspects of Siva. As we pointed out before, as the Idea of Rudra, as all the gods or, the Powers of Nature, was fully evolved, in Him was also centralized the various aspects of Nature as good and bad, awful and beneficent. Kalidasa playfully brings out this idea in the following lines:
"The Gods, like clouds, are fierce and gentle too Now hurl the bolt, now drop sweet heavenly dew In summer heat the streamlet dies away Beneath the fury of the God of day,
Then in due season comes the pleasant rain
And all is fresh and fair and full again."
However awful the aspect of a fierce storm, with its thunder and lightning, may be, yet no one can appreciate its beneficence more than the dwellers in the Indian soil, the land of so many famines. However fierce the sun may be, yet his existence is absolutely essential to the growth and maturity of all vegetation in the tropics. It will be noted that not only in the case of Rudra but in the case of other gods, their beneficent and malevolent powers are brought out in the Vedas. The Supreme Double Personality of Siva is thus explained in the Mahabharata by Lord Krishna himself. "Large armed Yudhishtira, understand from me, the greatness of the glorious, multiform, many named Rudra. They called Mahadeva, Agni, Sthanu, Mahesvara, one-eyed, Triyambaka, the Universal formed and Siva. Brahmans versed in the Veda know two bodies of this God, one awful, one auspicious ; and these two bodies have again many forms. The dire and awful body is fire, lightning, the sun: the auspicious and beautiful body is virtue, water and the moon. The half of his essence is fire and the other half is called the moon. The one which is his auspicious body practises chastity, while the other which is his most dreadful body, destroys the world.
From his being Lord and Great He is called Mahesvara. Since he consumes, since he is fiery, fierce, glorious, an eater of flesh, blood and marrow - he is called Rudra. As He is the greatest of the gods, as His domain is wide and as He preserves the vast Universe, - He is called Mahadeva. From his smoky colour, he is called Dhurjati. Since he constantly prospers all men in all their acts, seeking their welfare (Siva), He is therefore called Siva."* And in this, we see Him as not only the destroyer but as the Reproducer and Preserver and as such the conception of Siva transcends the conception of Rudra as one of the Trinity.
 
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