Simply by association with Me and My devotees, they achieved Me.

SB 11.12.1-2: The Supreme Personality of Godhead said: My dear Uddhava, by associating with My pure devotees one can destroy one's attachment for all objects of material sense gratification. Such purifying association brings Me under the control of My devotee. One may perform the aṣṭāńga-yoga system, engage in philosophical analysis of the elements of material nature, practice nonviolence and other ordinary principles of piety, chant the Vedas, perform penances, take to the renounced order of life, execute sacrificial performances and dig wells, plant trees and perform other public welfare activities, give in charity, carry out severe vows, worship the demigods, chant confidential mantras, visit holy places or accept major and minor disciplinary injunctions, but even by performing such activities one does not bring Me under his control.

SB 11.12.3-6: In every yuga many living entities entangled in the modes of passion and ignorance gained the association of My devotees. Thus, such living entities as the Daityas, Rākṣasas, birds, beasts, Gandharvas, Apsarās, Nāgas, Siddhas, Cāraṇas, Guhyakas and Vidyādharas, as well as such lower-class human beings as the vaiśyas, śūdras, women and others, were able to achieve My supreme abode. Vṛtrāsura, Prahlāda Mahārāja and others like them also achieved My abode by association with My devotees, as did personalities such as Vṛṣaparvā, Bali Mahārāja, Bāṇāsura, Maya, Vibhīṣaṇa, Sugrīva, Hanumān, Jāmbavān, Gajendra, Jaṭāyu, Tulādhāra, Dharma-vyādha, Kubjā, the gopīs in Vṛndāvana and the wives of the brāhmaṇas who were performing sacrifice.

SB 11.12.7: The persons I have mentioned did not undergo serious studies of the Vedic literature, nor did they worship great saintly persons, nor did they execute severe vows or austerities. Simply by association with Me and My devotees, they achieved Me.