Śatapatha Brāhmaṇa ("of a hundred paths") 9.1.2.19

9.1.2.19

virājo nāmeti | etadvai devā etā iṣṭakā nāmabhirupāhvayanti yathā-yathainā etadācakṣate tā enānabhyupāvartantātha lokampṛṇā eva parācyastasthurahitanāmnyo nimemihatyastā virājo nāmākurvata tā enānabhyupāvartanta tasmāddaśa-daśeṣṭakā upadhāya lokampṛṇayābhimantrayate tadenā virāvaḥ kurute daśākṣarā hi virāṭ kāmadudhā akṣīyamāṇā iti tadenāḥ kāmadudhā akṣīyamāṇāḥ kurute

'The widely-shining by name,'--for the gods then called those bricks to them by their names, and in the same way in which they called them, they turned unto them; but the 'space-fillers' alone stood with averted faces discharging water, having no names applied to them. They called them by the name 'the widely-shining,' and they turned unto them. Hence, each time he has laid down ten bricks, he addresses them with the 'space-filling (verse)': he thereby makes them widely-shining (virâg), for the Virâg (metre) consists of ten syllables:--'wish-milking, never-failing,'--he thereby makes them wish-milking and never-failing.