B.G 6.45
prayatnādyatamānastu yogī saṁśuddhakilbiṣaḥ। anekajanmasaṁsiddhastato yāti parāṁ gatim ॥45॥
Striving with effort, the yogi who is purified from sins and perfected through many births, then attains the supreme destination.
Gīta Bhāshya 6.45
The consistent effort that the seeker needs to put for a long period is stressed.
naikajanmani ityāha - prayatnāditi।
It is said that it is not just by multiple births but also through effort, by stating 'prayatnāditi' .
jijñāsuḥ jñātvā prayatnaṁ karoti। evam anekajanmabhiḥ saṁsiddhaḥ aparokṣajñānī bhūtvā parāṁ gatiṁ yāti। āha ca -
The seeker, having gained the knowledge of the path, makes an effort. Thus, through many births, having become perfected and gaining 'aparokṣa', i.e. direct perception of reality, he attains the supreme destination. It is also said-
"atīva śraddhayā yukto jijñāsurviṣṇutatparaḥ। jñātvā dhyātvā tathā dr̥ṣṭvā janmabhirbahubhiḥ pumān। viśennārāyaṇaṁ devaṁ nānyathā tu kathañcana॥"
"Endowed with intense inquisitiveness, the seeker becomes devoted to Vishnu. Having gained knowledge, meditating for many births, he finally sees directly and enters Lord Narayana, the divine. In no other way, indeed, this can be accomplished."
iti nāradīye ॥45॥
- stated thus in Naradiya Purana.