Bhakta adhikāra to attain perfection

1· By practice - sādhana

mārkaṇḍeyādayaḥ proktāḥ sādhanaiḥ prāpta-siddhayaḥ ||2.1.285||

"It is said that Mārkaṇḍeya and other sages attained perfection by sādhana."

2· By mercy - karuna

atha kṛpā-siddhāḥ, yathā śrī-daśame (10.23.43-44) -
nāsāṁ dvijāti-saṁskāro na nivāso gurāv api |
na tapo nātma-mīmāṁsā na śaucaṁ na kriyāḥ śubhāḥ ||2.1.286||
athāpi hy uttamaḥśloke kṛṣṇe yogeśvareśvare |
bhaktir dṛḍhā na cāsmākaṁ saṁskārādimatām api ||2.1.287||

An example of attaining perfection by mercy, from Śrīmad-Bhāgavatam [10.23.43-44]:

"These women have never undergone the purificatory rites of the twice-born classes,
nor have they lived as brahmacārīs in the āśrama of a spiritual master,
nor have they executed austerities, speculated on the nature of the self,
followed the formalities of cleanliness or engaged in pious rituals.
Nevertheless, they have firm devotion for Lord Kṛṣṇa, whose glories are chanted by the exalted hymns of the Vedas and who is the supreme master of all masters of mystic power.
We, on the other hand, have no such devotion for the Lord, although we have executed all these processes."

yathā vā -
na kācid abhavad guror bhajana-yantraṇe'bhijñatā
na sādhana-vidhau ca te śrama-lavasya gandho'py abhūt |
gato'si caritārthatāṁ paramahaṁsa-mṛgya-śriyā
mukunda-pada-padmayoḥ praṇaya-sīdhuno dhārayā ||2.1.288||

Another example:

"You are not known to have suffered pains in the service of the guru,
and you have trace of exerting even a drop of labor in following the rules of sādhana.
But you have succeeded in attaining the river of nectar of prema coming from
the two lotus feet of Mukunda, which are the wealth sought by the paramahaṁsas."

kṛpā-siddhā yajña-patnī-vairocani-śukādayaḥ ||2.1.289||

"Those who have attained perfection by mercy are Śuka,
the wives of the brāḥmaṇas and Bali, the son of Virocana."