वैष्णवं तेज आसाद्य समशाम्यद् भृगूद्वह ॥ १५ ॥
tv amoghaṁ cāpratikriyam
vaiṣṇavaṁ teja āsādya
yadyapi — although; astram — weapon; brahma-śiraḥ — supreme; tu — but; amogham — without check; ca — and; apratikriyam — not to be counteracted; vaiṣṇavam — in relation with Viṣṇu; tejaḥ — strength; āsādya — being confronted with; samaśāmyat — was neutralized; bhṛgu-udvaha — O glory of the family of Bhṛgu.
O Śaunaka, glory of Bhṛgu’s family, although the supreme brahmāstra weapon released by Aśvatthāmā was irresistible and without check or counteraction, it was neutralized and foiled when confronted by the strength of Viṣṇu [Lord Kṛṣṇa].
In the Bhagavad-gītā it is said that the brahmajyoti, or the glowing transcendental effulgence, is resting on Lord Śrī Kṛṣṇa. In other words, the glowing effulgence known as brahma-tejas is nothing but the rays of the Lord, just as the sun rays are rays of the sun disc. So this Brahma weapon also, although materially irresistible, could not surpass the supreme strength of the Lord. The weapon called brahmāstra, released by Aśvatthāmā, was neutralized and foiled by Lord Śrī Kṛṣṇa by His own energy; that is to say, He did not wait for any other’s help because He is absolute.