YV 5.2d

He who knows thus the boon of sky and earth [5] attains a boon. Indra thus impelled by these two slew Vrtra. The gods having slain Vrtra said to Agni and Soma, 'Bear the offering for us.' They said, 'We two have lost our brilliance, our brilliance is in Vrtra.' They said, 'Who is there to go for it?' 'The cow', they said, 'The cow is the friend of all.' She said [6], 'Let me choose a boon; ye shall feed off both when they are in me.' The cow brought the (brilliance); therefore they feed off both things that are in the cow; ghee indeed is the brilliance of Agni, milk the brilliance of Soma. He who knows thus the brilliance of Agni and Soma becomes brilliant. The theologians say, 'What is the deity of the full moon (rite)?' He should reply, 'Prajapati; by means of it he established his eldest son, Indra.' Therefore they establish their eldest sons with wealth. When Indra had slain Vrtra, his enemies threatened him. He saw this enemy- dispelling (oblation) to be offered subsequently at the full moon. He offered it, and with it drove away his enemies. In that the enemy-dispelling (oblation) is to be offered subsequently at the full moon, the sacrificer by it drives away his enemies. Indra, having slain Vrtra, lost the gods and his power. He saw the (offering) to Agni on eight potsherds at the new moon, and the curds for Indra [1]. He offered it, and by it he won the gods and his power. In that at the new moon there is (an offering) to Agni on eight potsherds, and curds for Indra, the sacrificer wins by it the gods and power. When Indra had slain Vrtra, his power and strength went into the earth; then the plants and roots were born. He ran up to Prajapati, (saying), 'Now that I have slain Vrtra, my power and strength [2] have gone into the earth; then the plants and roots have been born.' Prajapati said to cattle, 'Collect it for him.' The cattle collected it from the plants in themselves; they milked it.