Jaiminīya Upaniṣad Brāhmaṇa 3.32.1

3.32.1

tad dha sātyakīrtā āhur yāṃ vayaṃ devatām upāsmaha ekam eva vayaṃ tasyai devatāyai rūpaṃ gavy ādiśāma ekaṃ vāhana ekaṃ hastiny ekam puruṣa ekaṃ sarveṣu bhūteṣu
tasyā evedaṃ devatāyai sarvaṃ rūpam iti /

As to that, the Sātyakīrtas say: "Whichever deity we revere, we designate one and the same form of that deity in cattle, one in the draft-animal, one in the elephant, one in man, one in all beings. All this is the form of that deity alone."