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].
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
यद्यप्यस्त्रं ब्रह्मशिरस्त्वमोघं चाप्रतिक्रियम् । वैष्णवं तेज आसाद्य समशाम्यद्भृगूद्वह
yadyapyastraṃ brahmaśirastvamoghaṃ cāpratikriyam | vaiṣṇavaṃ teja āsādya samaśāmyadbhṛgūdvaha
SB 1.8.15