अथ यदेतदादित्यस्य शुक्लं भाः सैवर्गथ यन्नीलं परः कृष्णं तत्साम तदेतदेतस्यामृच्यध्यूढं साम तस्मादृच्यध्यूढं साम गीयते ॥ १.६.५ ॥
In plain words
Now the white light of the sun is the Ṛc, and the dark blue that is beyond black is the Sāman. This Sāman rests upon that Ṛc; therefore the Sāman is sung as resting upon the Ṛc.