Shatapatha Brahmana 2.6.1.42

2.6.1.42

atha nīvimudvṛhya namaskaroti | pitṛdevatyā vai nīvistasmānnīvimudvṛhya namaskaroti yajño vai namo yajñiyānevainānetatkaroti ṣaṭ kṛtvo namaskaroti ṣaḍvā ṛtava ṛtavaḥ pitarastadṛtuṣvevaitadyajñam pratiṣṭhāpayati tasmātṣaṭ kṛtvo namaskaroti gṛhānnaḥ pitaro datteti gṛhāṇāṃ ha pitara īśata eṣo etasyāśīḥ karmaṇaḥ

He then pulls down the tuck (of the nether garment) and makes obeisance (to the Fathers). The tuck, doubtless, is sacred to the Fathers: hence he makes obeisance to them after pulling down the tuck; and obeisance means worship: hence he thereby recognises them as entitled to worship. Six times he makes obeisance to them, since there are six seasons, and the Fathers are the seasons: hence he thereby establishes his sacrifice in the seasons,--that is why he makes obeisance six times. 'Give houses unto us; O Fathers!' he (further) says, because the Fathers are the guardians of houses;--and this is the prayer for blessing at this sacred performance.