What is the Mantra to invoke the Brahmastra? It is the Gayatri Mantra, intoned in a specific way. It is by altering the sound waves in the Ether that the Brahmastra got its potency. Sound is referred to as the “Nada Brahma” or the divine sound, that is to say, in abstraction too there is a connection with the divine. Jun 4, 2014