स्वायम्भुव ब्रह्मसत्रं जनलोकेऽभवत् पुरा ।
तत्रस्थानां मानसानां मुनीनामूर्ध्वरेतसाम् ॥ ९ ॥
jana-loke ’bhavat purā
śrī-bhagavān uvāca — the Supreme Lord said; svāyambhuva — O son of self-born Brahmā; brahma — performed by the utterance of transcendental sound; satram — a sacrifice; jana-loke — on the planet Janaloka; abhavat — occurred; purā — in the past; tatra — there; sthānām — among those who resided; mānasānām — born from the mind (of Brahmā); munīnām — sages; ūrdhva — (flowing) upward; retasām — whose semen.
The Personality of Godhead said: O son of self-born Brahmā, once long ago on Janaloka, wise sages who resided there performed a great sacrifice to the Absolute Truth by vibrating transcendental sounds. These sages, mental sons of Brahmā, were all perfect celibates.
Śrīla Śrīdhara Svāmī explains that the word satram here refers to a Vedic sacrifice in which all the participants are equally qualified to serve as priests. In this instance, each of the sages present in Janaloka could speak equally well on the topic of Brahman.