Shatapatha Brahmana 11.2.4.8

11.2.4.8

tadāhuḥ yanna pūrṇamāsāyeti havirgṛhyate na darśāyeti havirgṛhyate na pūrṇamāsāyānubrūhi na darśāyānubrūhi na pūrṇamāsaṃ yaja na darśaṃ yajetyatha kenāsya darśapūrṇamāsāviṣṭau bhavata iti sa yam manasa āghārayati mano vai pūrṇamāstena pūrṇamāsaṃ yajatyatha yaṃ vāca āghārayati vāgvai darśasteno darśaṃ yajatyeteno hāsya darśapūrn\amāsāviṣṭau bhavataḥ

As to this they say,--'Seeing that no offering-material is taken out "for the full moon," nor any offering-material "for the new moon," and seeing that he does not say, "Recite the invitatory formula for the full moon," nor "Recite the invitatory formula for the new moon;" nor "Recite the offering-formula for the full moon," nor "Recite the offering-formula for the new moon," how, then, is offering made to this full and new moon?' Well, when he makes a libation of ghee to the Mind--the full moon being the Mind--he thereby makes offering to the full moon; and when he makes a libation of ghee to Speech--the new moon being Speech--he thereby makes offering to the new moon: and thus offering is made by him to the full and new moon.