Jaiminīya (Talavakāra) Brāhmaṇa 2-2.12

'That indeed was the eldest in the worlds'—that is the form of the chariot; therefore they stand striding over it. 'O rock-bearer, being praised as great'—that is the form of an elephant; therefore they mount it from the side. These indeed turn into great forms; Prajāpati is indeed of great form. The Mahāvrata belongs to Prajāpati; each [stotra] is made with that characteristic. These forms wait unbought upon him who knows thus. 'This devotion of mine to you two' is the indrāgni [stotra]. 'Indra and Agni, the ancient praise was born like rain from a cloud'—by 'was born' they mean 'produced.' And he is born through this day. Just as here [young birds] would break out of an egg, so indeed they break out of this day. 'Hear the call of the singer, O Indra and Agni; accept his words, O ye who are capable, nourish our thoughts! Let us not come to evil, O heroes Indra and Agni, nor to reproach; do not deliver us to censure!'—thus this is the warding off of evil.

'Upward is your juice born'—the verses with the word 'andhas' of the midday pavamāna are gāyatrīs. They belong to Prajāpati; on the day of Prajāpati, each is made with that characteristic.