Shatapatha Brahmana 11.5.9.1

11.5.9.1

prajāpatirha vā eṣa yadaṃśuḥ so'syaiṣa ātmaivātmā hyayam prajāpatirvāgevādābhyaḥ sa yadaṃśuḥ gṛhītvādābhyaṃ gṛhṇātyātmānamevāsyaitatsaṃskṛtya tasminnetāṃ vācam pratiṣṭhāpayati

Now, the Amsu (cup of Soma), indeed, is no other than Pragâpati; and it is the body of this (sacrifice), for Pragâpati, indeed, is the body. And the Adâbhya (cup of Soma) is no other than speech. When he draws the Amsu-cup, and then the Adâbhya-cup, he thereby constructs the body of this (sacrifice) and then establishes that speech therein.