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SB 7.15.73

tāvad dāsyām ahaṁ jajñe
 tatrāpi brahma-vādinām
śuśrūṣayānuṣaṅgeṇa
 prāpto ’haṁ brahma-putratām
Synonyms: 
tāvat — since being cursed; dāsyām — in the womb of a maidservant; aham — I; jajñe — took birth; tatrāpi — although (being a śūdra); brahma-vādinām — unto persons well conversant with the Vedic knowledge; śuśrūṣayā — by rendering service; anuṣaṅgeṇa — simultaneously; prāptaḥ — obtained; aham — I; brahma-putratām — a birth as the son of Lord Brahmā (in this life).
Translation: 
Although I took birth as a śūdra from the womb of a maidservant, I engaged in the service of Vaiṣṇavas who were well-versed in Vedic knowledge. Consequently, in this life I got the opportunity to take birth as the son of Lord Brahmā.
Purport: 

The Supreme Personality of Godhead says in Bhagavad-gītā (9.32):

māṁ hi pārtha vyapāśritya
 ye ’pi syuḥ pāpa-yonayaḥ
striyo vaiśyās tathā śūdrās
 te ’pi yānti parāṁ gatim

“O son of Pṛthā, those who take shelter in Me, though they be of lower birth — women, vaiśyas [merchants], as well as śūdras [workers] — can approach the supreme destination.” It doesn’t matter whether a person is born as a śūdra, a woman or a vaiśya; if he associates with devotees repeatedly or always (sādhu-saṅgena), he can be elevated to the highest perfection. Nārada Muni is explaining this in relation to his own life. The saṅkīrtana movement is important, for regardless of whether one is a śūdra, vaiśya, mleccha, yavana or whatever, if one associates with a pure devotee, follows his instructions and serves the pure devotee, his life is successful. This is bhakti. Ānukūlyena kṛṣṇānuśīlanam. Bhakti consists of serving Kṛṣṇa and His devotees very favorably. Anyābhilāṣitā-śūnyam. If one has no desire other than to serve Kṛṣṇa and His devotee, then his life is successful. This is explained by Nārada Muni through this practical example from his own life.