एतेन मंत्रराजेन सर्वोपनिषदात्मना । लेभिरे मुनयः सर्वे परं ब्रह्म निरामयम्
etena maṃtrarājena sarvopaniṣadātmanā | lebhire munayaḥ sarve paraṃ brahma nirāmayam
Durch diesen König der Mantras, dessen Wesen alle Upaniṣaden sind, erlangten alle Weisen das höchste Brahman, frei von jedem Leid und Makel.
Deductive attribution: Purāṇic narrator in Brahmottara-khaṇḍa (likely Sūta/compilational voice)
The Śiva-mantra is equated with Upaniṣadic wisdom and is said to lead to realization of the supreme Brahman.
No tīrtha is mentioned; the emphasis is on mantra as a direct spiritual means.
Reliance on (and practice of) the mantra—especially japa—as the means to the highest attainment.