Skanda Purana — Mahesvara Khanda, Shloka 102
प्रणम्य च ततो भक्त्या स्नापयेन्मूलमंत्रतः । ओंहूं विश्वमूर्तये शिवाय नम । इति द्वादशाक्षरो मूलमंत्रः
praṇamya ca tato bhaktyā snāpayenmūlamaṃtrataḥ | oṃhūṃ viśvamūrtaye śivāya nama | iti dvādaśākṣaro mūlamaṃtraḥ
随后，怀敬信而顶礼，应以根本真言为（林伽）沐浴：“唵 吽——敬礼宇宙形相之湿婆（Oṃ hūṃ viśvamūrtaye śivāya namaḥ）。”此即所称十二音节根本真言。
Lomaharṣaṇa (Sūta) to the sages (deduced from Māheśvarakhaṇḍa context)
Scene: A devotee folds hands and bows before the liṅga, then begins abhiṣeka while chanting the mūla-mantra; the sanctum seems to expand symbolically into the cosmic form of Śiva.
FAQs
True worship is devotion expressed through mantra—recognizing Śiva as the very form of the universe.
No specific tīrtha is mentioned; the emphasis is on mantra-based Śiva abhiṣeka.
After bowing, bathe the liṅga while reciting the mūlamantra: “oṃ hūṃ viśvamūrtaye śivāya namaḥ,” identified here as a dvādaśākṣara mantra.