तस्मा आदित्याश्च विश्वे च देवास्तृतीयसवनं सम्प्रयच्छन्त्येष ह वै यज्ञस्य मात्रां वेद य एवं वेद य एवं वेद ॥ २.२४.१६ ॥
In plain words
And the Ādityas and the All-gods bestow on him the third pressing. He knows the full measure of the sacrifice who knows this — who knows this.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
एष ह वै यजमान एववित् यथोक्तस्य सामादेर्विद्वान् यज्ञस्य मात्रा यज्ञयाथात्म्य वेद यथोक्तम् । य एव वेदेति द्विरुक्तिरध्यायपरिसमाप्त्यर्था ॥
In plain words
This person is truly the knower of the sacrifice. Understanding the sāman and other elements as described, he knows the true nature and measure of the sacrifice. The repetition of 'whoever thus knows' marks the conclusion of the chapter.
Close to the Sanskrit
This indeed is the sacrificer who knows thus; knowing the aforementioned sāman and other elements, he knows the measure and true nature of the sacrifice as stated. The repetition 'whoever thus knows' is for the purpose of concluding the chapter.