Śatapatha Brāhmaṇa ("of a hundred paths") 14.1.3.1

14.1.3.1

sa yadaitadātithyena pracarati atha pravargyeṇa cariṣyanpuropasado'greṇa gārhapatyam prācaḥ kuśāntsaṃstīrya dvandvam pātrāṇyupasādayatyupayamanīm mahāvīram parīṣāsau pinvane rauhiṇakapāle rauhiṇahavanyau srucau yadu cānyadbhavati taddaśa daśākṣarā vai virāḍvirāḍvai yajñastadvirājamevaitadyajñamabhisampādayatyatha yaddvandvamdvandvam vai vīryam yadā vai dvau saṃrabhete atha tau vīryaṃ kuruto dvandvam vai mithunam prajananam mithunenaivainametatprajananena samardhayati kṛtsnaṃ karoti

Now at the time when he there proceeds with the guest-meal, he who intends to perform the Pravargya, prior to the Upasads, spreads Kusa grass with its tops directed towards the east, in front of the Gârhapatya, and places the vessels thereon in pairs,--the Upayamanî (tray) and the Mahâvîra (pot), the pair of lifting-sticks, the two milking-bowls, the two Rauhina-plates, the two offering spoons for the Rauhina (cakes), and whatever other (implement) there is,--these make ten, for the Virâg consists of ten syllables, and the sacrifice is Virâg: he thus makes this to be equal to the Virâg, the sacrifice. And as to their being in pairs,--a pair means strength, for when two take hold of each other they exert strength; and a pair (couple) means a productive union: with a productive union he thus supplies and completes it.