Bhagavad Gita 9.2

राजविद्या राजगुह्यं पवित्रमिदमुत्तमम्।प्रत्यक्षावगमं धर्म्यं सुसुखं कर्तुमव्ययम्॥

rājavidyā rājaguhyaṃ pavitramidamuttamam |pratyakṣāvagamaṃ dharmyaṃ susukhaṃ kartumavyayam ||

This is the royal science, the royal secret, the supreme purifier, realizable by direct intuitive knowledge, according to righteousness, very easy to perform and imperishable.

This is the supreme science, the supreme secret, the purest and best; it is intuitive, righteous, and to those who practice it, it is exceedingly pleasant.

Our plain-language meaning of this verse is waiting for scholar review.