Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.2.16

4.1.2.16

antaste dyāvāpṛthivī dadhāmi | antardadhāmyurvantarikṣam sajūrdevebhiravaraiḥ paraiśceti tadenaṃ vaiśvadevaṃ karoti tadyadenenemāḥ prajāḥ prāṇatyaścodanatyaścāntarikṣamanucaranti tena vaiśvadevo 'ntaryāme maghavanmādayasvetīndro vai maghavānindro yajñasya netā tasmādāha maghavannityatha yadantarantariti gṛhṇātyantastvātmandadha ityevaitadāha

'Into thee I lay day and night; into thee I lay the wide air: allied with the gods, the lower and the higher,'--thereby he makes this (graha) one belonging to all the gods: because by means of it these creatures move about in the air breathing out and breathing in, therefore it belongs to all the gods.--'Delight thyself in the Antaryâma, O mighty one!' the mighty one is Indra, and Indra is the leader of the sacrifice, wherefore he says 'O mighty one!' and in that he draws it with 'into--into,' thereby he means to say 'I lay thee into his (Indra's) self.'