Śatapatha Brāhmaṇa ("of a hundred paths") 1.3.5.10

1.3.5.10

saptadaśa sāmidhenīḥ | iṣṭya anubrūyādupāṃśu tasyai devatāyai yajati yasyā iṣṭaṃ nirvapati dvādaśa vai māsāḥ saṃvatsarasya pañcartava eṣa eva prajāpatiḥ saptadaśaḥ sarvaṃ vai prajāpatistatsarveṇaiva taṃ kāmamanaparādhaṃ rādhnoti yasmai kāmāyeṣṭiṃ nirvapatyupāṃśu devatām yajatyaniruktaṃ vā upāṃśu sarvaṃ vā aniruktaṃ tatsarveṇaiva taṃ kāmamanaparādhaṃ rādhnoti ṣvasmai kāmāyeṣṭhiṃ nirvapatyeṣa iṣṭerupacāraḥ

For an ishti (which is performed in order to obtain the fulfilment of a special wish) let him recite seventeen sâmidhenî verses; for in a low voice he sacrifices to the deity to which he offers an ishti. Twelve months, namely, there are in a year, and five seasons: this (makes) the seventeenfold Pragâpati. For verily Pragâpati is all: hence for what wish he performs the ishti, that wish he thus accomplishes by means of the All. In a low voice he sacrifices to the deity; for what is spoken in a low voice is undefined (indistinct), and undefined is the 'All:' hence for whatever wish he performs the ishti, that wish he thus accomplishes by means of the All. This is the practice in regard to an ishti.