Śatapatha Brāhmaṇa ("of a hundred paths") 3.4.2.9

3.4.2.9

te devāḥ | juṣṭāstanūḥ priyāṇi dhāmāni sārdhaṃ samavadadire 'thaita ājyānyeva gṛhṇānā juṣṭāstanūḥ priyāṇi dhāmāni sārdhaṃ samavadyante tasmādu ha na sarveṇeva samabhyaveyānnenme juṣṭāstanvaḥ priyāṇi dhāmāni sārdhaṃ samabhyavāyāniti yeno ha samabhyaveyānnāsmai druhyedidaṃ hyāhurna satānunaptriṇe drogdhavyamiti

The gods laid down together their favourite forms and desirable powers. Now it is by taking portions of butter that they (the priests) lay down together the desirable forms and favourite powers. Let him, then, not covenant with any one and every one, lest his favourite forms and desirable powers should be mixed up (with those of others). But let him not deceive one with whom he makes a covenant; for thus it is said, 'Let there be no deceiving of him with whom one has made the covenant of Tanûnapât.'