Vaishnava Dharmashastra 23.47

23.47

trīṇi devāḥ pavitrāṇi brāhmaṇānām akalpayan
adṛṣṭam adbhir nirṇiktaṃ yac ca vācā praśasyate //

The gods have declared, as peculiar to Brâhmanas, three causes effecting purity: if an (existing) impurity has not been perceived by them; if they, sprinkle the object (supposed to be impure) with water; and if they commend it, in doubtful cases, with their speech, (saying, 'This or that shall be pure.')