Aitareyabrahmana 5.8

5.8

'Forward this prayer when Vṛtra is defeated, thou hast aided' [ṚV 6.17] is a hymn in paṅkti, five-footed, on the fifth day: [it is] the form of the fifth day.
'Indra has grown for intoxication' [ṚV 6.18] is a hymn possessing intoxication (madvat), in paṅkti, five-footed, on the fifth day: [it is] the form of the fifth day.
'Wholly universal are thy intoxications' [ṚV 6.19] is a hymn possessing intoxication (madvat), in triṣṭubh.
With it, having a firmly established verse-quarter, he supports the soma pressing; by this he does not slip from his own abode.
'That Indra we strengthen' [ṚV 8.93.7] is the concluding triplet (paryāsa); 'He became a bull, a virile bull' [ṚV 8.93.7c] is the form of cattle, on the fifth day: [it is] the form of the fifth day.
And these are gāyatrīs.
The gāyatrīs indeed carry the midday [pressing] of this three-day period.
That metre indeed carries [it] into which the nivid is placed.
Therefore he places the nivid into the gāyatrīs.
'That of Savitṛ we choose' [ṚV 5.82.1], 'Today for us, god Savitṛ' [ṚV 5.82.4] are the opening verse and the following verse of the Vaiśvadeva [śastra],
on a Rathantara day, on the fifth day: [it is] the form of the fifth day.
'Upward that god Savitṛ, the protector of the home' [ṚV 6.71] is the hymn to Savitṛ; 'He impels abundant wealth for the worshipper' [ṚV 6.71.1c]—wealth (vāmam) is the form of cattle, on the fifth day: [it is] the form of the fifth day.
'The two great Heaven and Earth here, the oldest' [ṚV 6.70] is the hymn to Heaven and Earth; 'May the bull roar' [ṚV 6.70.2d] is the form of cattle, on the fifth day: [it is] the form of the fifth day.
'Ṛbhu, Vibhvan, Vāja, Indra towards us' [ṚV 4.34] is the hymn to the Ṛbhus;
vāja indeed is cattle; it is the form of cattle, on the fifth day: [it is] the form of the fifth day.
'I praise the folk of good vows with newest [hymns]' [ṚV 6.21] is the hymn to the All-gods, possessing repetitions, the form of cattle, on the fifth day: [it is] the form of the fifth day.
'The drink of the sacrificial offering, unaging, winning the sun' [ṚV 6.4] is the opening verse of the Āgnimāruta [śastra]; possessing sacrificial offering (haviṣmat), on the fifth day: [it is] the form of the fifth day.
'Let that wonderful form (vapuḥ) now appear to him who is discerning' [ṚV 6.66] is the hymn to the Maruts; possessing a wonderful form (vapuṣmat), on the fifth day: [it is] the form of the fifth day.
'For Jātavedas let us press the soma' [ṚV 1.99.1] is the constant verse to Jātavedas.
'Agni the hotṛ, lord of the house, he is king' [ṚV 4.7] is the hymn to Jātavedas, possessing repetitions, the form of cattle, on the fifth day: [it is] the form of the fifth day.