उमामहेश्वरव्रतं—पञ्चाक्षरमन्त्रस्य माहात्म्यं, न्यासः, जपविधिः, सदाचारः, विनियोगः
ब्रह्मचारिगृहस्थानां यतीनां चैव शोभने सशिरस्कं ततो देहं सर्वमन्त्रेण संस्पृशेत्
brahmacārigṛhasthānāṃ yatīnāṃ caiva śobhane saśiraskaṃ tato dehaṃ sarvamantreṇa saṃspṛśet
ब्रह्मचारिगृहस्थानां यतीनां चैव शोभने । सशिरस्कं ततो देहं सर्वमन्त्रेण संस्पृशेत् ॥
Suta Goswami (narrating Shiva-puja procedure within the Linga Purana’s discourse)
It prescribes a preparatory purification: the devotee sanctifies the whole body (including the head) by mantra-touch, making the body a fit instrument for approaching the Linga as Pati (Śiva).
Śiva is implied as the supreme purifier: through mantra connected to Him, the embodied pashu (soul) refines the psycho-physical field, loosening pāśa (bondage) and turning the body-mind toward Śiva-consciousness.
Mantra-sparśa (ritual touching with mantra) as a purification limb of Śiva-pūjā—aligned with Pāśupata discipline where bodily acts are consecrated by mantra before worship.