Śatapatha Brāhmaṇa ("of a hundred paths") 2.3.1.24

2.3.1.24

taddvayamevaite āhutī | bhūtaṃ caiva bhaviṣyacca jātaṃ ca janiṣyamāṇaṃ cāgataṃ cāśā cādya ca śvaśca taddvayamevānu

These two libations, then, form a duad: the past and the future, the born and the to-be-born, the actual and the hope, the to-day and the morrow,--(these are) after the manner of that duad.