Rudra, The epithet of Lord Shiva: an Introduction

Rudra, ( रुद्र), is associated as the Rig Vedic storm god, known for his benevolence and endowment of knowledge. The name loosely translated comes as the Howler, the Roarer. The name in actuality has 4 root meanings, (1) Dreadful or terrific, (2) Great or Large (3) Drive away evil (4) Worthy of praise. Another meaning is that the root word "Ru" is usually considered to teach and "dra" is considered as flow. Thus we get flow of knowledge. As a result, Rudra is considered the deity who teaches knowledge to all those who seek it. He is seen as the destructive force of nature as well. Unlike classical theology, Shaiva Siddanta views god a being present in everything. Shiva is not merely just a creator who looks after the universe, but is present in every animate/inanimate good/bad beautiful/ugly entity. The unique aspect of his worship is that the devotee worships all his cosmic forms.

Rudra: The Fierce one

However, despite this, one must not confuse oneself with the thought that Rudra is a destructive force, who punishes and destroys. Quite the contrary, Rudra is a benevolent deity who confers prosperity, offspring and cattle. Not only is he known for bringer of prosperity but also of knowledge. The verse RV 6.49.10 calls Rudra as " The Father of the Universe" (bhuvanasya pitaraṃ)

  

bhuvanasya pitaraṃ ghīrbhirābhī rudraṃ divā vardhayā rudramaktau
bṛhantaṃ ṛṣvamajaraṃ suṣumnaṃ ṛdhagh ghuvema kavineṣitāsaḥ (RV 6 :49:10)

 Translation: 

Rudra by day, Rudra at night we honour with these our songs, the Universe's Father. Him great and lofty, blissful, undecaying let us call specially as the Sage impels us ( RV 6.49.10)^*The Rig Veda, trans. Ralph T.H. Griffith [1896]

The Sage Rudra

The verse RV 2.33.9 calls Rudra as "The Lord or Sovereign of the Universe" 
(īśānādasya bhuvanasya)

sthirebhiraṅghaiḥ pururūpa ughro babhruḥ śukrebhiḥ pipiśehiraṇyaiḥ īśānādasya bhuvanasya bhūrerna vā u yoṣad rudrādasuryam (Rig veda 2:33:9 )

 Translation

With firm limbs, multiform, the strong, the tawny adorns himself with bright gold decorations: The strength of Godhead never departs from Rudra, him who is Sovereign of this world, the mighty. The Rig Veda, trans. Ralph T.H. Griffith [1896]

He is pleased by chanting the legendary Rudram which occurs in the Krishna Yajur Veda of the Vedas. Rudram is also known as Shatarudriya, Rudraprashna or Rudradhyaya. The Jabala upanishad, from the vedas claim that he who chants the Shatarudriya obtains immortality. The text Shri Rudram is also famous for its mention of its Shaivite Panchakshari Mantra (NAMA SHIVAAYA) which is considered as the holiest of all mantras within the Yajur Veda. The Panchakshari mantra occurs in the middle of Sri Rudram and hence considered the most important within the Shatarudriya. The chanting of Shatarudriyam is considered of utmost benefit which has the capacity to burn sins and confer wealth and prosperity to the chanter.