Śatapatha Brāhmaṇa ("of a hundred paths") 13.3.4.2

13.3.4.2

te'bruvan agnayaḥ sviṣṭakṛto'śvasya vayamuddhāramuddharāmahai tenāsurānabhibhaviṣyāma iti te lohitamudaharanta bhrātṛvyābhibhūtyai yatsviṣṭakṛdbhyo lohitaṃ juhoti bhrātṛvyābhibhūtyai bhavatyātmanā parāsya dviṣanbhrātṛvyo bhavati ya evaṃ veda

They (the gods) spake, 'We are the Agnayah Svishtakritah of the horse (sacrifice); let us take out for ourselves a special share: therewith we shall overcome the Asuras.' They took the blood for themselves in order to overcome their rivals; when he offers the blood to the Svishtakrits, it is in order to overcome (his own) rivals; and the spiteful rival of him who knows this is undone by himself.