Bhagavad Gita, Chapter 9, Verse 2

राजविद्या राजगुह्यं पवित्रमिदमुत्तमम् । प्रत्यक्षावगमं धर्म्यं सुसुखं कर्तुमव्ययम्

rājavidyā rājaguhyaṃ pavitramidamuttamam | pratyakṣāvagamaṃ dharmyaṃ susukhaṃ kartumavyayam

Translation

The Sovereign Science, the Sovereign Secret, the Supreme Purifier is this; immediately comprehensible, unopposed to Dharma, very easy to perform, imperishable.

— Alladi Mahadeva Sastri

Word meanings

rājavidyā

of sciences, the king

rājaguhyam

of secrets, the king

pavitram

purifier

idam

this

uttamam

highest

pratyakṣāvagamam

by direct (intuition), knowledge

dharmyam

righteous

susukham

very happy

kartum

to do

avyayam

imperishable

Śaṅkarācārya's commentary

Of sciences it is the king, because it is of great splendour. Indeed, the science of Brahman is the most brilliant of all sciences. It is also the king of secrets. Of all the purifiers, this knowledge of Brahman is the best purifier: it reduces karma to ashes in an instant, root and all — all the karma, dharma and adharma, accumulated during many thousand births. Moreover, it can be comprehended by pratyakṣa, by immediate perception, like the feeling of pleasure. What is possessed of many a desirable quality may be opposed to dharma; but not so is the knowledge of Ātman. It is very easy to acquire, like the power of discriminating gems. And, unlike acts, it is imperishable: it does not perish when its effect is exhausted.