Lecture Notes on the Sūtra of the Collection of the Father and Son (Pitāputrasamāgamanasūtra), Part Three

After sentient beings attain buddhahood, they possess the thirty-two marks and the eighty secondary marks, one of which is the mark of the "Brahmā voice"—the Buddha's voice is exceedingly wondrous and clear; when hundreds of billions of humans and devas come to hear the Dharma, no amplifier is needed, and everyone can hear it. Moreover, not only can humans understand the language the Buddha speaks, but ghosts and spirits can also understand it, animals can also understand it, and sentient beings of the six realms can all understand it; Chinese people can understand it, and people of other countries can also understand it; people of different languages and different races can all understand it, and the bodhisattvas of other buddha-lands can all understand it, and all can hear the Buddha's voice clearly. This is one of the Buddha's virtues.

Brahmā conduct is pure conduct; when the body, speech, and mind attain purity, free from the defilement of desire, that is brahmā conduct. The perfection of pure conduct is the perfection of brahmā conduct—when the mind has no mental actions defiled by greed, hatred, and delusion, the mind attains purity. What the World-Honored One is now expounding is the dharma of the divisions and positions of the six elements, namely the six great elements of earth, water, fire, wind, space, and consciousness—the divisions and positions, definitions, differentiations, boundaries, functions, and other such questions of these six dharmas.