God is Omnipresent and All-pervasive. By the nature of these qualities, He cannot have a form, and, is therefore formless – ‘aroovam’ in Tamil. But for our sake, He also assumes innumerable forms – 'uruvams'. Lingam in which form we worship Isvara is symbolic both of ‘uruvam’, because there is a particular shape, and of ‘aroovam’ as there is neither a head nor limbs like other images. Lingam denotes something which has neither a beginning nor end. The literal meaning of Lingam is a symbol.
A prime manifestation of a formless form is Lingothbhavamoorthi. It was thus that He made his appearance at midnight on Sivarathri and devotees keep vigil at that time and worship Siva.
In any important Siva temple one will find a niche in the outer wall of the sanctum sanctorum, exactly behind the place where the main deity is installed. In that niche there will be a representation of Lingothbhavamoorthi – a form emerging out of a Lingam, with neither the top of the head, nor the bottom of the foot, visible in that form. All the other attributes of Siva will be there. There will also be the image of a swan in flight at the top and a boar burrowing the earth at the bottom. According to legend, Brahma took the form of swan to find out the crown of Siva's head and could not; and, Vishnu the form of boar, or varaaha, dug deep into the bowels of the earth to find Siva’s feet and failed. Thus in Lingothbhavamoorthi, we have a unique combination of Brahma, Vishnu and Siva.
God, in his manifestation as Vishnu, made his appearance as Krishna at Gokulam at midnight – celebrated as Goklashtami. Exactly 180 days after that day, Sivarathri occurs, when Siva, as Lingodbhavamoorthi, made his appearance, also at midnight. Thus the cycle of one year is divided into two by these two auspicious days, when in one form or the other, God, makes his appearance.
Lingothbhavamoorthi stands out in all majesty to remind us that out of His formlessness, Iswara emerged in a form for our benefit. It is our duty on that day to fast, to keep awake and worship Him, particularly at midnight, preferably with at least one leaf of the bilva tree.
Jaya Jaya Sankara, Hara Hara Sankara