Vayupurana 1.26.23

Vāyupurāṇa 1.26.23

tato vedaṃ dvimātraṃ tu dṛṣṭvā caiva tadakṣaram.
dvimātraṃ cintayan brahma tvakṣaraṃ punarīśvaraḥ .. 26.21 ..