इयमेवर्गग्निः साम तदेतदेतस्यामृच्यध्यूढ़ं साम तस्मादृच्यध्यूढंसाम गीयत इयमेव साग्निरमस्तत्साम ॥ १.६.१ ॥
In plain words
This earth is the Ṛc and fire is the Sāman. This Sāman rests upon that Ṛc; therefore the Sāman is sung as resting upon the Ṛc. This earth is sā and fire is ama, and that makes sāman.