This question is asked all too often, not only by westerners or newcomers to Sanatana Hindu Dharma, but even by born Hindus who practice without knowing the context of what we practice.
Some scholars give their own- sometimes ridiculous- interpretations, saying things like, “we pour milk and ghee on the Linga to prevent the stone from cracking.” While this might sound like a joke, it was literally offered by a well known guru as a scientific reason for abhishekham. If this were truly the reason, then why do we pour milk and ghee on lingas made of gold, silver, copper or pancha loka, the five metal combination? And why do we not pour milk and ghee on the temple structures themselves, and the ground, which are also made of stone? Would they not be cracking and crumbling if a lack of milk and ghee led to stone breakage?
In the Kamika Agama, Mahadeva Himself, Lord Sadashiva, extolls milk as amrita, the elixir of the divine, as it comes from Gaumata, the sacred mother cow, who is an embodiment of purity and non violence. Sadashiva also gives the complete instruction on how this should be offered, not to feed and appease Him who is beyond all worldly need, but to establish a connection between ourselves and Him. When we pour out the best of what we have for Him, our relationship is solidified tangibly.
A similar anti-Hindu thought current to that which tries to explain abhishekham as a mere physical practice to clean or protect the Linga is the thought current that attempts to render moot the purpose for this form of puja. Some will dryly say Sadashiva is everywhere, not just in the form of the Linga or the Moorthi, so why not worship Him everywhere instead of in a limited physical way?
To this, His Holiness Paramahamsa Nithyananda once said beautifully, “As long as you are alive in a physical body, worship should be physical.”
The concept of omnipresence and omniscience is beyond humanly fathom. We can’t visualize Sadashiva everywhere; we can’t recognize Him in everything. For this reason, in compassion to us, Sadashiva has given the form of the Linga, which is a solidification of His beginninglessness and endlessness; it is the shaft of light as which He appeared to settle the dispute of grandeur between Brahma and Vishnu, neither of whom could find His head or His feet. When we physically pour milk, honey, flowers, ghee, and the best of whatever we have, to Him, our devotion, finding expression in a way we can relate to and understand, is made real. Just as you would give milk to your own child, give it to your own Sadashiva. Just as you would prepare a meal for your beloved, prepare Naivedyam for Him. Just as you would care for your dear father, care for Your Father who is Maha Sadashiva. Puja, abhiskekam, is not a dry dull ritual for appeasing some higher force; it’s your intimate time to connect with and take care of your cosmic beloved.
Truly devotional Hindus don’t need a calculated scientific reason to shower the Linga with milk, ghee, honey, curd, turmeric, sandalwood paste, flowers and more. Shiva Bhaktas enjoy the Oneness we experience by overflowing in the form of the puja. Next time you offer milk, remember this: you’re not pouring liquid on a statue in order to fulfill a divine instruction; you’re pouring your love onto your Sadashiva in order to strengthen your relationship.