Patanjali Yoga Sutra — दृष्टा दृशिमात्रः शुद्धोऽपि प्रत्ययानुपश्यः ॥2.20॥

dṛṣṭā dṛśimātraḥ śuddho’pi pratyayānupaśyaḥ॥

ātman also called Seer, Soul, Consciousness, Puruṣa, dṛk, sat, Experiencer, Dehī or Kṣetrajña is pure, unchangeable consciousness forever. He is not dependent on prakṛti, but always a silent spectator of the prakṛti (thus, keeps Himself aloof and untainted from the influences of prakṛti and its constituents called Triguṇas).

The message of sūtra 2.17 is repeated here in a more emphatic and comprehensive way, bringing out the nature of ātman.

Bhagavān describes ātman on similar lines:

यथा प्रकाशयत्येकः कृत्स्नं लोकमिमं रविः।

क्षेत्रं क्षेत्री तथा कृत्स्नं प्रकाशयति भारत॥गीता १३.३३॥

अनादित्वान्निर्गुणत्वात्परमात्मायमव्ययः।

शरीरस्थोऽपि कौन्तेय न करोति न लिप्यपे॥गीता १३.३१॥

yathā prakāśayatyekaḥ kṛtsnaṃ lokamimaṃ raviḥ|

kñetraṃ kñetrī tathā kṛtsnaṃ prakāśayati bhārata॥Gītā 13.33॥

anāditvānnirguṇatvātparamātmāyamavyayaḥ|

śarīrastho’pi kaunteya na karoti na lipyate॥Gītā 13.31॥

The only Sun illuminates the entire universe. Similarly, the only ātman (or kṣetrajña or Dehī pervading in all) sources the life force in all bodies (or kñetras). This Kṣetrajña is without a beginning (and end), beyond all the Triguṇas, and though being the indwelling ātman, never executes any karmas. Thus remains untainted forever.

Sometimes, gullible readers might get confused and find it difficult to digest these kinds of messages. But our upanṣads have a very effective and unique method of teaching. That is, complex messages are taught through stories so that it catches the imagination of readers. In kaṭhopaniṣad, the power of ātman is imparted to the readers by way of a story, where different parts of the human body are the characters in a play-like situation. Finally, all these parts of the body accept the supremacy of ātman. Even a novice can easily understand and remember the message given. Aśvamedhayāga is a very complex and long ritual involving almost one full year. All through this full year, the sacrificer and his family members have to hear the recital of several stories (called Pāriplavas), so that their interest and commitment to yajña ritual is held and sustained all through. The translation of the word pariplava could be ‘swaying or moving to and fro in water’. That means an anecdote that can help avoid this kind of swaying or moving to and fro.