Bhagavad Gita 4.2

एवं परम्पराप्राप्तमिमं राजर्षयो विदु:
स कालेनेह महता योगो नष्ट: परन्तप  ॥

evaṃ paramparā-prāptam-imaṃ rājarṣayo vidu:
sa kāleneha mahatā yogo naṣṭa: parantapa – 4.2 

This yoga (spiritual science), handed down thus through the Guru-śishya lineage, was possessed well by the Knower kings (Rajarshis). But by passage of inexorable time, it has got lost, O scorcher of enemies!