Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.4.14

4.3.4.14

atha hiraṇyamādāya śālāmabhyaiti | dakṣiṇena vediṃ dakṣiṇā upatiṣṭhante so 'greṇa śālāṃ tiṣṭhannabhimantrayate rūpeṇa vo rūpamabhyāgāmiti na ha vā agre paśavo dānāya cakṣamire te 'panidhāya svāni rupāṇi śarīraiḥ pratyupātiṣṭhanta tānetaddevāḥ svaireva rūpairyajñasyārdhādupāyaṃste svāni rūpāṇi jānānā abhyavāyaṃste rātamanaso 'laṃ dānāyābhavaṃstatho evaināneṣa etatsvaireva rūpairyajñasyārdhādupaiti te svāni rūpāṇi jānānā abhyavāyanti te rātamanaso 'laṃ dānāya bhavanti

Thereupon, taking some gold, (the sacrificer) goes to the hall. South of the altar stand the Dakshinâ (cows). Standing in front of the hall, he respectfully addresses them with (Vâg. S. VII, 45), 'By your beauty have I come to beauty.' Now at first cattle did not submit to being given away. Laying aside their own beauteous forms they approached with their (bare) bodies. The gods then went up to them from the offering ground with their (the animals’) own forms; and they, knowing their own forms, resigned themselves and became well-disposed to being given away. And in like manner does he now go up to them from the offering ground with their own forms; and they, knowing their own forms, resign themselves and become well-disposed to being given away.