The works of Ādi Śaṅkarācārya

Viṣṇusahasranāmastotram

Verse 213

नाविष्णुः कीर्तयेद्विष्णुं नाविष्णुर्विष्णुमर्चयेत् ।नाविष्णुः संस्मरेद्विष्णुं नाविष्णुर्विष्णुमाप्नुयात् ॥

In plain words

One who is not Viṣṇu cannot sing Viṣṇu. One who is not Viṣṇu cannot worship Viṣṇu. One who is not Viṣṇu cannot hold Viṣṇu in mind. One who is not Viṣṇu cannot reach Viṣṇu.

Close to the Sanskrit

A non-Viṣṇu does not praise Viṣṇu; a non-Viṣṇu does not worship Viṣṇu; a non-Viṣṇu does not remember Viṣṇu; a non-Viṣṇu does not attain Viṣṇu.