sabhāyāṃ yasya vidyante
sabhāyām—in the assembly; yasya—whose; vidyante— are present; mūrti-mantaḥ—in person; artha- bodhakāḥ—who express the truth; yat—whose; catuḥ-vaktrataḥ—from the four mouths; jātāḥ—born; purāṇa—the Purāṇas; nigama—Vedas; ādayaḥ—and other scriptures.
48. Present in person in your assembly are the Vedas, Purāṇas, and other scriptures, the revealers of truth, who were born from your four mouths.
Although the four Vedas are eternal, they enter the material world periodically, at the beginning of each day of Brahmā, when one Veda appears from each of his four mouths. Brahmā, therefore, is not the author of the Vedas, which include all spiritual and material knowledge, but he is ādi-kavi, the first authority on Vedic knowledge in this universe.