उमामहेश्वरव्रतं—पञ्चाक्षरमन्त्रस्य माहात्म्यं, न्यासः, जपविधिः, सदाचारः, विनियोगः
ओमित्येकाक्षरं मन्त्रं स्थितः सर्वगतः शिवः मन्त्रे षडक्षरे सूक्ष्मे पञ्चाक्षरतनुः शिवः
omityekākṣaraṃ mantraṃ sthitaḥ sarvagataḥ śivaḥ mantre ṣaḍakṣare sūkṣme pañcākṣaratanuḥ śivaḥ
ಏಕಾಕ್ಷರ ಮಂತ್ರ ‘ಓಂ’ನಲ್ಲಿ ಸರ್ವಗತ ಶಿವನು ಸ್ಥಿತನಾಗಿದ್ದಾನೆ. ಹಾಗೆಯೇ ಸೂಕ್ಷ್ಮ ಷಡಕ್ಷರ ಮಂತ್ರದಲ್ಲಿ ಶಿವನು ಪಂಚಾಕ್ಷರೀ-ತನುವಾಗಿ ವಿರಾಜಿಸುತ್ತಾನೆ.
Suta Goswami (narrating the Linga Purana’s teaching to the sages of Naimisharanya)
It anchors Linga-upāsanā in mantra-upāsanā: the Linga’s all-pervading Shiva-tattva is approached through Om and through the Pañcākṣarī (Namaḥ Śivāya), making japa a direct mode of worship.
Shiva is presented as sarvagata (all-pervading) and simultaneously accessible in subtle mantra-form—Pati who pervades all while revealing himself through sound (śabda) to liberate the paśu from pāśa.
Mantra-japa as Pāśupata-oriented sādhana: contemplation of Om along with steady repetition of Namaḥ Śivāya as the subtle embodiment of Shiva for inner purification and release from bondage.