The works of Ādi Śaṅkarācārya

Viṣṇusahasranāmastotram

Verse 112

एक एव महानात्मा सोऽहंकारोऽभिधीयते ।स जीवः सोऽन्तरात्मेति गीयते तत्त्वचिन्तकैः ॥

In plain words

The great Self alone is one; He is named the ego, celebrated as the individual soul, and described as the inner witness by those who contemplate ultimate truth.

Close to the Sanskrit

The great Self alone is one; He is designated as the ego, He is sung as the individual soul, He is described as the inner self by seekers of truth.