Śatapatha Brāhmaṇa ("of a hundred paths") 3.4.4.21

3.4.4.21

sa yatsāyamprātaḥ pracarati | tathā hyeva sampatsampadyate sa yatpūrvāhṇe pracarati tajjayatyatha yadaparāhṇe pracarati sujitamasadityatha yajjuhotīdaṃ vai puraṃ yudyanti tāṃ jitvā svāṃ satīṃ prapadyante

As to his performing in the evening and in the morning,--it is because only thus completeness is obtained. When he performs in the forenoon, then he gains the victory;--and when he performs in the afternoon, he does so that it may be a good (complete) victory;--and when he offers the Homa, (it is as if) people fight here for a stronghold, and having conquered it, they enter it as their own.