The works of Ādi Śaṅkarācārya

Viṣṇusahasranāmastotram

Verse 180

त्यम्' इत्यादिभ्यः श्रुतिभ्यः ।

In plain words

Because the Veda itself says so — the passage that opens 'tyam...' and the others like it.

Close to the Sanskrit

From the śruti passages beginning with 'tyam' and the rest.