Aitareyabrahmana 5.10

5.10

pārucchepīr upadadhati pūrvayoḥ savanayoḥ purastāt prasthitayājyānāṃ.
rohitaṃ vai nāmaitac chando yat pārucchepam.
etena vā Indraḥ sapta svargām̐l lokān arohad
rohati sapta svargām̐l lokan ya evaṃ veda
tad āhur:
yat pañcapadā eva pañcamasyāhno rūpaṃ ṣaṭpadāḥ ṣaṣṭhasyātha
kasmāt saptapadāḥ ṣaṣṭhe 'hañ chasyanta iti
ṣaḍbhir eva padaiḥ ṣaṣṭham ahar āpnuvanty apachidyevaitad ahar
yat saptamaṃ, tad eva saptamena padenābhyārabhya vasanti.
vācam eva tat punar upayanti, saṃtatyai
saṃtatais tryahair avyavachinnair yanti ya evaṃ vidvāṃso yanti

v. 10 (xxii. 5). In the first two pressings he inserts (verses) by Parucchepa before the offering verses for the Prasthita libations; the metre of the Parucchepa (verses) is the mounting; by it Indra mounted the seven worlds of heaven; he mounts the seven worlds of heaven, who knows thus. They say ‘Seeing that (verses) of five Padas are a symbol of the fifth day, and (verses) of six Padas of the sixth, then why are (verses) of seven Padas recited on the sixth day?’ By six Padas they make up the sixth day, cutting off as it were the seventh day; that they keep grasping by the seventh Pada. Verily thus they approach speech again, for continuity. With sets of three days, uninterrupted and continuous, they proceed who proceed knowing thus.