Śatapatha Brāhmaṇa ("of a hundred paths") 5.2.3.10

5.2.3.10

atha cāturmāsyairyajate | sarvānvā eṣa yajñakratūnavarunddhe sarvā iṣṭīrapi darvihomānyo rājasūyena yajate devasṛṣṭo vā eṣa yajñakraturyaccāturmāsyānyebhirme 'pīṣṭamasadebhirapi sūyā iti tasmāccāturmāsyairyajate

Thereupon he performs the Seasonal offerings; for verily he who performs the Râgasûya secures for himself (the benefits of) all sacrificial rites, all ishtis, even the spoon-offerings; and instituted by the gods, in truth, is that sacrificial rite, the Seasonal offerings: 'May these also be offered by me! May I be consecrated by these (offerings) also!' thus he thinks, and therefore he performs the Seasonal offerings.