Agnibheda–Vaṃśa: Forms of Agni, Their Functions, and Progeny (अग्निभेद-वंशः)
मथितो यस्त्वरण्यां च सो ऽग्निरग्निं समिन्धति / आयुर्नाम्ना तु भगवानसौ यस्तु प्रणीयते
mathito yastvaraṇyāṃ ca so 'gniragniṃ samindhati / āyurnāmnā tu bhagavānasau yastu praṇīyate
The fire kindled by churning wood in the forest is the very fire that enflames the fire. That Blessed Lord is known by the name Āyu, and is led forth according to rite.