Verse 1.3.7

द्यौरेवोदन्तरिक्षं गीः पृथिवी थमादित्य एवोद्वायुर्गीरग्निस्थं सामवेद एवोद्यजुर्वेदो गीरृग्वेदस्थं दुग्धेऽस्मै वाग्दोहं यो वाचो दोहोऽन्नवानन्नादो भवति य एतान्येवं विद्वानुद्गीथाक्षराण्युपास्त उद्गीथ इति ॥ १.३.७ ॥

dyaurevodantarikṣaṃ gīḥ pṛthivī thamāditya evodvāyurgīragnisthaṃ sāmaveda evodyajurvedo gīrṛgvedasthaṃ dugdhe'smai vāgdohaṃ yo vāco doho'nnavānannādo bhavati ya etānyevaṃ vidvānudgīthākṣarāṇyupāsta udgītha iti || 1.3.7 ||

7. Heaven is ut, the space between heaven and the earth is gī, and the earth is tha. The sun is ut, air is gī, and fire is tha. The Sāma Veda is ut, the Yajur Veda is gī, and the Ṛg Veda is tha. The scriptures reveal their meaning to the seeker if he knows all this. One who worships ut-gī-tha as above gets plenty of food and also eats plenty of food. [Such a person also gets enlightenment.]

Word-for-word explanation:

Dyauḥ, heaven; eva ut, is ut; antarikṣam gīḥ, the space between heaven and earth is gī; pṛthivī tham, the earth is tha; ādityaḥ eva ut, the sun is ut; vāyuḥ gīḥ, air is gī; agniḥ tham, fire is tha; sāma vedaḥ eva ut, the Sāma Veda is ut; yajur vedaḥ gīḥ, the Yajur Veda is gī; ṛg vedaḥ tham, the Ṛg Veda is tha; vāk, the Ṛg Veda and other scriptures; asmai, to him [the spiritual seeker]; doham, the goal [he is seeking]; dugdhe, gives him of itself; yaḥ vācaḥ dohaḥ, the goal is the knowledge of the scriptures; yaḥ evam vidvān, the seeker who knows this; etāni udgīthākṣarāṇi ut + gī + tha iti upāste, [and] worships these syllables of udgītha; annavān, he has plenty of food; annādaḥ bhavati, [and] he enjoys eating that food [i.e., he becomes illumined].

Commentary:

Heaven is said to be ut because it is high above. Space is gī because it envelops the whole world.

And the earth is tha because it is the support of all beings. Āditya, the sun, is ut because it is far above everything. Vāyu, air, is gī because it envelops everything. Agni, fire, is tha because it is the common element in every sacrificial rite. The Sāma Veda is said to be ut because it is known even in heaven. The Yajur Veda is gī because the butter used in performing the Yajur Vedic rites is eaten by the gods and goddesses. The Ṛg Veda is tha because it supports the Sāma Veda.

What do you gain by worshipping ut-gī-tha? You gradually understand the meaning of the Ṛg Veda and other Vedas. You also have plenty to eat, and you become like ‘a blazing fire’—that is, you become an illumined person.