Śatapatha Brāhmaṇa ("of a hundred paths") 10.5.2.16

10.5.2.16

tau hṛdayasyākāśam pratyavetya mithunībhavatastau yadā mithunasyāntaṃ gacato'tha haitatpuruṣaḥ svapiti tadyathā haivedam mānuṣasya mithunasyāntaṃ gatvāsaṃvida iva bhavatyevaṃ haivaitadasaṃvida-iva bhavati daivaṃ hyetanmithunam paramo hyeṣa ānandaḥ

As to this they say, 'One death, or many?' Let him say, 'Both one and many;' for inasmuch as he is that (man in the sun) in yonder world he is one, and inasmuch as he is numerously distributed here on earth among living beings, there are also many of them.