Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.1.37

2.6.1.37

te sarva eva yajñopavītino bhūtvā | udañca upaniṣkramyāhavanīyamupatiṣṭhante devānvā eṣa upāvartate ya āhitāgnirbhavati yo darśapūrṇamāsābhyāṃ yajate 'thaitatpitṛyajñenevācāriṣustadu devebhyo nihnuvate

Thereupon they all, being sacrificially invested, walk out (of the shed) on the north side, (pass along the east side of, and) stand by the (north) side of, the Âhavanîya fire. For he who has established his fires, and performs the New and Full-moon sacrifices, approaches the gods; but they have just been performing the sacrifice to the Manes, and therefore they now propitiate the gods.