Udyoga Parva Adhyāya 103: Garuḍa’s Protest, Viṣṇu’s Demonstration, and Counsel Toward Śama
प्रादाच्छक्रस्ततस्तस्मै पन्नगायायुरुत्तमम् । न त्वेनममृतप्राशं चकार बलवृत्रहा,तब इन्द्रने उस नागको अच्छी आयु प्रदान की, परंतु बलासुर और वृत्रासुरका विनाश करनेवाले इन्द्रने उसे अमृतभोजी नहीं बनाया
prādāc chakras tatas tasmai pannagāyāyur uttamam | na tv enam amṛtaprāśaṃ cakāra balavṛtrahā ||
Vaiśaṃpāyana said: Then Śakra (Indra) granted that serpent an excellent span of life; yet Indra, the slayer of Bala and Vṛtra, did not make him an eater of amṛta (and thus not truly immortal).
वैशम्पायन उवाच
A boon can be generous yet bounded: Indra grants long life but withholds amṛta-based immortality, reflecting dharma as the maintenance of proportion and cosmic balance rather than indiscriminate reward.
Vaiśampāyana narrates that Indra (Śakra) rewards a nāga by granting an excellent lifespan, but does not confer the status of an amṛta-eater; Indra is identified by his heroic epithet as the slayer of Bala and Vṛtra.