Saṃjñā–Chāyā Upākhyāna: Sūrya-tejas, Substitution, and the Birth of Manu, Yama, and Yamunā
अधृष्यां सर्वभूतानां तेजसा नियमेन च । सोऽश्वरूपं समास्थाय गत्वा तां मैथुनेच्छया
adhṛṣyāṃ sarvabhūtānāṃ tejasā niyamena ca | so'śvarūpaṃ samāsthāya gatvā tāṃ maithunecchayā
Unassailable by all beings—by the force of his splendor and by the power of his disciplined resolve—he assumed the form of a horse and went to her, driven by desire for union.
Suta Goswami (narrating the Purana account to the sages, within the Uma-samhita narrative frame)
Tattva Level: pashu
The verse highlights how immense tejas (spiritual potency) combined with niyama (disciplined will) makes a being ‘unassailable’; it also shows that desire can appear in narrative as a force that must ultimately be governed and purified toward dharma and liberation.
By depicting Shiva’s assumption of a specific form, the text emphasizes saguna-līlā—Shiva manifesting through forms for cosmic play and instruction—supporting devotional contemplation that leads from form-based worship toward the formless, transcendent Pati.
The implied takeaway is niyama and sense-discipline: steady japa of the Panchakshara (Om Namaḥ Śivāya) and yogic restraint to transform desire into focused devotion and inner purity.