Śatapatha Brāhmaṇa ("of a hundred paths") 5.1.2.1

5.1.2.1

aṃśuṃ gṛhṇāti | sarvatvāyaiva tasmādvā aṃśuṃ gṛhṇātyathaitānprajñātānevāgniṣṭomikāngrahāngṛhṇātyāgrayaṇāt

He draws the Amsu (graha), just for completeness’ sake, for it is therefor that he draws the Amsu. After that he draws those recognised Agnishtoma cups up to the Âgrayana.
2, He then draws the Prishthyas: and whatever the gods (Agni, Indra, and Sûrya) won by them, even that he wins by them.