Bhagavatapurana 8.19.38

8.19.38

atrāpi bahvṛcairgītaṃ śṛṇu me 'surasattama /
satyamomiti yat proktaṃ yan nety āhānṛtaṃ hi tat //

38. Further there is the saying of Rigvedins on this point, O great Asura, listen to me:--whatever is accepted by uttering the sacred syllable is called Satya and whatever is denied by saying '*No*' is said to be Falsehood.