Chapter 6 · The Yoga of Meditation · Krishna said
Bhagavad Gita 6.45 — Perfection over many lives
प्रयत्नाद्यतमानस्तु योगी संशुद्धकिल्बिषः। अनेकजन्मसंसिद्धस्ततो याति परां गतिम् ॥
prayatnādyatamānastu yogī saṃśuddhakilbiṣaḥ | anekajanmasaṃsiddhastato yāti parāṃ gatim ||
Meaning
The yogi who strives with diligence, cleansed of sin and perfected over many births, finally reaches the supreme goal.