चक्षुरेवर्गात्मा साम तदेतदेतस्यामृच्यध्यूढंसाम तस्मादृच्यध्यूढंसाम गीयते ।चक्षुरेव सात्मामस्तत्साम ॥ १.७.२ ॥
In plain words
The eye is the Ṛc and the self is the Sāman. This Sāman rests upon that Ṛc; therefore the Sāman is sung as resting upon the Ṛc. The eye is sā and the self is ama, and that makes sāman.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
चक्षुरेव ऋक् आत्मा साम । आत्मेति च्छायात्मा, तत्स्थत्वात्साम ॥
In plain words
The eye itself is the ṛk, and the self is the sāman. This self is the shadow in the eye, and because it rests there, it is known as the sāman.
Close to the Sanskrit
The eye indeed is ṛk, the self is sāman. The self thus is the shadow-self, because of abiding therein, it is sāman.