text: Rudra is one of the names of Vishnu in Vishnu Sahasranama. Adi Shankara in his commentary to Vishnu Sahasranama defined the name Rudra as 'One who makes all beings cry at the time of cosmic dissolution'.  Author D. A. Desai in his glossary for the Vishnu Sahasranama says Vishnu in the form of Rudra is the one who does the total destruction at the time of great dissolution. This is only the context known where Vishnu is revered as Rudra.
  Rigvedic hymns
  The earliest known mentions of the Vedic deity Rudra, occur in the Rigveda, where three entire hymns are devoted to him (RV 1.114, 2.33, and 7.46). Two further hymns are devoted to Rudra jointly with Soma (RV 1.43 and 6.74). There are about seventy-five references to Rudra in the Rigveda overall.
  Form of Rudra
  In the Rigveda (RV) are verses which speak about the form of Rudra. Some of them are:
  Epithets of fierceness and fright
  In the Rigveda, Rudra's role as a frightening god is apparent in references to him as ghora ('extremely terrifying'), or simply as asau devam ('that god'). He is 'fierce like a terrific wild beast' (RV 2.33.11). Chakravarti sums up the perception of Rudra by saying: 'Rudra is thus regarded with a kind of cringing fear, as a deity whose wrath is to be deprecated and whose favor curried'.
  RV 1.114 is an appeal to Rudra for mercy, where he is referred to as 'mighty Rudra, the god with braided hair'.