ब्रह्मवादिनो वदन्ति यद्वसूनां प्रातः सवनं रुद्राणां माध्यंदिनं सवनमादित्यानां च विश्वेषां च देवानां तृतीयसवनम् ॥ २.२४.१ ॥
In plain words
Those who speak of Brahman say: The morning pressing belongs to the Vasus, the midday pressing to the Rudras, and the third pressing to the Ādityas and the All-gods.
The commentators
Chāndogyopaniṣadbhāṣyam
सामोपासनप्रसङ्गेन कर्मगुणभूतत्वाभिवर्त्य ओंकार पर मात्मप्रतीकत्वादमृतत्वहेतुत्वेन महीकृत्य प्रकृतस्यैव यज्ञस्य अङ्गभूतानि सामहोममन्त्रोत्थानान्युपदिदिक्षन्नाह—
ब्रह्मवादिनो वदन्ति, यत्प्रात सवन प्रसिद्धं तद्वसूनाम् । तैश्च प्रात सवनसम्बद्धोऽय लोको वशीकृत प्रात सवनेशानै । तथा रुद्रैर्माध्यन्दिनसवनेशानै अन्तरिक्षलोक । आदित्यैश्च विश्वैर्देवैश्च तृतीयसवनेशानैस्तृतीयो लोको वशीकृत । इति यजमानस्य लोकोऽन्य परिशिष्टो न विद्यते ॥
In plain words
In the course of discussing meditation on the Sama chant, the text exalts the syllable Om because it represents the Supreme Self and leads to immortality, serving as an important accessory to ritual action. Wishing now to teach those chants and sacrificial mantras derived from the Sama which form the limbs of the ongoing sacrifice, the scripture says:
The knowers of Brahman state: The well-known morning pressing belongs to the Vasus. As lords of that morning session, they have brought this earthly world under their control. Likewise, the Rudras, as lords of the midday pressing, control the atmosphere, and the Ādityas and Viśvedevas, as lords of the evening pressing, control the heavenly world. Thus, no other world remains for the sacrificer to conquer.
Close to the Sanskrit
In the context of meditating on the Sama, having elevated Om—because it is a symbol of the Supreme Self and the cause of immortality, as it serves as an accessory to ritual action—wishing to teach the risings of the Sama oblations and mantras which are limbs of the sacrifice under discussion, he speaks:
The expounders of Brahman say: That morning pressing which is well known belongs to the Vasus. And by them, as lords of the morning pressing, this earthly world is brought under control. Similarly, by the Rudras as lords of the midday pressing, the mid-space world; and by the Ādityas and the Viśvedevas as lords of the third pressing, the third world is brought under control. Thus no other world remains for the sacrificer.