Ramayana — Yuddha Kanda, Sarga 71, Shloka 103
अतिकायवधः
The Slaying of Atikāya
ब्रह्मदत्तवरोह्येषअवध्यकवचावृतः ।ब्राह्मेणास्त्रेणभ्निथ्येनमेषवध्योहिनान्यथा ।।।।अवध्यएषह्यन्येषामस्त्राणांकवचीबली ।
brahmadattavaro hy eṣa avadhyakavacāvṛtaḥ |
brāhmeṇāstreṇa bhindhy enam eṣa vadhyo hi nānyathā ||
avadhya eṣa hy anyeṣām astrāṇāṃ kavacī balī ||
He bears a boon granted by Brahmā and is clad in inviolable armor. Pierce him with the Brahmā-weapon—only then can he be slain, not otherwise. For, armored and mighty, he is invulnerable to all other weapons.
By the boon given by Brahma his body is covered with armour which can't be broken. By Brahma's weapon only you can strike to kill him because of his armour and might. By any other weapon it is not possible to kill him.
FAQs
It underscores maryādā (lawful constraint) in warfare: power must be exercised within rightful limits, using the appropriate means rather than indiscriminate force.
It presents a factual constraint about invulnerability and the true method to overcome it—truthful knowledge guiding action, not mere strength or guesswork.