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.