nArudrO rudramarchayEt is usually quoted by the performers
of mahanyAsa pUrvaka rudrAbhishEka ritual as an explanation
for the anganyaasa karanyaasa portions of the ritual in which
the performer does aavaahana (the supernatural process of
bringing and filling the spirit into one's own self) of rudra
onto himself.
Similar anganyaasa karanyaasa portions form the early part
of archanaa of many other dEvas. nAdevo devam arcayet is
probably an extension of the statement nArudrO rudramarchayEt
to the rituals other than rudrAbhiShEka.
--
Prof.Nagaraj Paturi
Hyderabad-500044