Verse 1.1.2

एषां भूतानां पृथिवी रसः पृथिव्या अपो रसः । अपामोषधयो रस ओषधीनां पुरुषो रसः पुरुषस्य वाग्रसो वाच ऋग्रस ऋचः साम रसः साम्न उद्गीथो रसः ॥ १.१.२ ॥

eṣāṃ bhūtānāṃ pṛthivī rasaḥ pṛthivyā apo rasaḥ | apāmoṣadhayo rasa oṣadhīnāṃ puruṣo rasaḥ puruṣasya vāgraso vāca ṛgrasa ṛcaḥ sāma rasaḥ sāmna udgītho rasaḥ || 1.1.2 ||

2. The earth is the essence of all things, living or non-living; water is the essence of the earth; plants are the essence of water; human beings are the essence of plants; speech is the essence of human beings; the Ṛg Veda is the essence of speech; the Sāma Veda is the essence of the Ṛg Veda; and the udhītha is the essence of the Sāma Veda.

Word-for-word explanation:

Eṣām bhūtānām, of these beings; pṛthivī rasaḥ, the earth is the essence; pṛthivyāḥ, of the earth; āpaḥ, water; rasaḥ, is the essence; apām oṣadhayaḥ rasaḥ, plants are the essence of water; oṣadhīnām puruṣaḥ rasaḥ, human beings are the essence of plants; puruṣasya vāk rasaḥ, speech is the essence of human beings; vācaḥ ṛg rasaḥ, the Ṛg Veda is the essence of speech; ṛcaḥ sāma rasaḥ, the Sāma Veda is the essence of the Ṛg Veda; sāmnaḥ udgīthaḥ rasaḥ, the part known as udgītha is the essence of the Sāma Veda.

Commentary:

There are both living and non-living things on the earth. What sustains them? Obviously the earth. They all come out of the earth, are sustained by the earth, and finally dissolve into the earth. But what sustains the earth? Water. The earth is a mixture of water and earth, and there can be no earth without water.

Plants are said to be the essence of water, for they grow from water. Similarly, human beings are the essence of plants, because the human body is the outcome of the food eaten by human beings. Speech is the essence of human beings, for it is the best part of them. The best speech is the Ṛg Veda, and the essence of the Ṛg Veda is the Sāma Veda. Finally, udgītha—that is, Om—is the essence of the Sāma Veda.