As per Shiv Puran, the origin of the lingam described as the beginning-less and endless cosmic pillar (Stambha) of fire, the cause of all causes. Bhagwan Shiv is pictured as emerging from the lingam – the cosmic pillar of fire – proving his superiority over the gods Brahma and Vishnu.
It is said that the Supreme Shiv appeared before Bhagwan Brahma and Vishnu in the form of a ‘pillar of fire’, which had no end and beginning. This is mentioned in Purans like Brahmand Puran, Ling Puran. It is one among the many symbols of the Brahman, the Supreme. So the linga form of Shiv also signifies the column of bright light.
If we accumulate all the information and heard discourses, the conclusion would be: Linga represents the first knowledge that a human has an evolved being understood. Linga represents the formless Mahakaal who existed when there was nothing (shunya) and who will exist when there will be everything (infinity) the Yoni which acts as a base for the linga represents Maha Shakti (the Energy that creates and destroys).
According to the legend, The incarnation of Bjagwan Shiva as ‘Ardhanareeswar’ is well explained through the creation of Siva Linga. This divine appearance is the union of half man and half woman which formed by the equal halves of Bhagwan Shiv and his consort Mata Parvathi. Hence the benefit of worshipping Ardhanareeswar can be easily acquired by offering rituals to Shiva Lingam. The blessings available from the structure assure peaceful and lifelong association of husband and wife which is considered as the foundation of solid family life.