Śatapatha Brāhmaṇa ("of a hundred paths") 4.6.7.8

4.6.7.8

tasmādu kurvantyeva sadasi | yajuṣṭaudumbarīmucrayanti sadaḥ saminvanti dhiṣṇyānupakirantyevaṃ hi sayujāvabhavatām

And hence they also perform with the Yagus in the Sadas: they raise up the Udumbara post, they erect the Sadas, they throw up the dhishnya hearths,--for thus they became yoke-fellows.