The works of Ādi Śaṅkarācārya

Svarūpānusandhānāṣṭakam

Verse 3

यदानन्दरूपं प्रकाशस्वरूपंनिरस्तप्रपञ्चं परिच्छेदहीनम् ।अहम्ब्रह्मवृत्त्यैकगम्यं तुरीयंपरं ब्रह्म नित्यं तदेवाहमस्मि ॥ ३ ॥

In plain words

Bliss is its form. Light is its own nature. In it the whole spread-out world is thrown off, and no boundary cuts it anywhere. One movement of the mind alone reaches it — I am Brahman. It is turīya, the fourth; it is the supreme Brahman, eternal. That, exactly that, is what I am.

Close to the Sanskrit

That which is bliss in form, whose own nature is light, in which the manifold is cast out, devoid of all delimitation, reachable by the mental mode 'I am Brahman' alone, the fourth, the supreme Brahman, eternal — that very thing I am.