Jaiminīya (Talavakāra) Brāhmaṇa 2.260

Thereby he places the ear: two ears and two surrounding cavities. Therefore, being in the same place, one hears in all directions. Even when facing away, one hears someone speaking from behind. He should sing it meditating. If he were to sing without meditating, deaf embryos would be born. Deaf indeed are the embryos born in the course of a bad Udgātṛ. He sings the Anuṣṭubh. The Anuṣṭubh is speech. He sings it driving it towards himself, so that speech will not depart. If he were to sing it driving it away, he would blow speech away; speech would depart from him. When he sings it driving it towards himself, he establishes speech in his very self. He sings two quarters of it, one explicitly stated and one unexpressed. By the explicitly stated part of speech they make use of it; its unexpressed part is that by which one subsists. One who knows thus makes use of speech and subsists by it. If he were to sing only the explicitly stated, creatures would only speak and would not sit silent. And if he were to sing the unexpressed, creatures would only sit silent and would not speak. Because he sings both an explicitly stated and an unexpressed quarter, therefore creatures both speak and sit silent.

He should sing it strongly, with a stomping sound, striking down.

For indeed, the meter that is Anuṣṭubh is like a smiter.

By means of speech, the Anuṣṭubh meter, the gods struck down the Asuras into silence.

When he sings it strongly, with a stomping sound, striking down—the rival is evil—

he strikes down into silence this evil rival, and attains prosperity for himself.

He should sing it meditating.

If he were to sing without meditating, tongueless embryos would be born.

Tongueless indeed are the embryos born in the course of a bad Udgātṛ.