Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.1.4

4.3.1.4

yadveva sanne 'cāvāke | ṛtugrahaiścarati sarvaṃ vā ṛtavaḥ saṃvatsaraḥ sarvamevaitatprajanayati tasmātsanne 'cāvāka ṛtugrahaiścarati

And again why he proceeds with the libations of the seasons, when the Akhâvâka is seated. The seasons, the year, are everything; he thus produces everything: this is why he proceeds with the libations of the seasons when the Akhâvâka is seated.