Bhagavad Gita 4.2 Chapter 4, Verse 2

एवं परम्पराप्राप्तमिमं राजर्षयो विदुः ।
स कालेनेह महता योगो नष्टः परन्तप ॥४.२॥

evaṃ paramparāprāptamimaṃ rājarṣayo viduḥ
sa kāleneha mahatā yogo naṣṭaḥ parantapa

Meaning

Handed down in this way, the royal sages knew it. But over a long period of time, O scorcher of foes, this yoga was lost to the world.

Newly written by Bhajan Dhun — scholarly review in progress.

Reference: Bhagavad Gita 4.2 (Chapter 4, The Yoga of Knowledge and Renunciation of Action, Verse 2)