Chandogya Upanishad 4.3.6

4.3.6

sa hovāca \
mahātmanaś caturo deva ekaḥ kaḥ sa jagāra bhuvanasya gopāḥ \
taṃ kāpeya nābhipaśyanti martyā abhipratārin bahudhā vasantam \
yasmai vā etad annaṃ tasmai etan na dattam iti \\403.6\

6. Then he said:— “One God (deva) has swallowed up four mighty beings (mahātman). Who is that world’s protector, O Kāpeya? Him mortal men perceive not, though abiding In manifolded forms, Abhipratārin. Verily, this food has not been offered to whom it belongs.”