Vighneshvara-Prashna and Deva-Krita Shiva-Stava
Adhyaya 104
ओङ्कारे त्रिविधं रूपम् आस्थायोपरिवासिने पीताय कृष्णवर्णाय रक्तायात्यन्ततेजसे
oṅkāre trividhaṃ rūpam āsthāyoparivāsine pītāya kṛṣṇavarṇāya raktāyātyantatejase
ओंकारात अधिष्ठित होऊन आपण त्रिविध रूप धारण करता—ऊर्ध्वस्थ परात्पर प्रभू; पीत, कृष्णवर्ण व रक्तरूप; आणि अत्यंत तेजस्वी।
Suta Goswami (narrating Linga Purana teachings to the sages of Naimisharanya)
It identifies Oṃ (Pranava) as the subtle seat of the Linga-principle: the worshipper contemplates Shiva as the transcendent Pati who manifests in a threefold way, making Omkara-dhyana a direct support for Linga-upasana.
Shiva is portrayed as atyanta-tejas (limitless consciousness-radiance) who remains ‘above’ as transcendent, yet expresses Himself through differentiated appearances (the three colors/forms), indicating both nirguna transcendence and saguna manifestation.
Pranava-upasana: meditative absorption on Oṃ as Shiva’s sonic body, used in Pashupata-oriented contemplation to loosen pasha (bondage) and steady the pashu (soul) in awareness of the Pati.