Śatapatha Brāhmaṇa ("of a hundred paths") 1.6.3.21

1.6.3.21

atha ha soma uvāca | māmeva vaḥ sarvebhyo juhvatu tadvo 'haṃ mayyābhajāmīti tasmātsomaṃ sarvebhyo devebhyo juhvati tasmādāhuḥ somaḥ sarvā devatā iti

Soma then said, 'Me they shall offer up to all of you, and thus I give you a share in me!' For this reason they offer up Soma to all the gods; and hence they say that Soma is all the deities.