Śrīman Mahāprabhu’s gift is revealed through the ācāryas.
This Rādhā-dāsya is an unprecedented gift of mercy. The conditioned souls are floating in the ocean of material existence, but by some stroke of good luck some of them receive the mercy of guru and Kṛṣṇa in the form of the seed of the vine of devotion.

saṁsāre bhramite kon bhāgyavān jīva;
guru-Kṛṣṇa prasāde pāy bhakti latā bīja
(C.C.)

By taking shelter of the lotus-feet of Śrī Guru a fortunate person can attain purification of the self. Gurudeva is bringing the awareness of this into our hearts. When fortunate sādhakas take shelter of Śrī Guru’s lotus-feet in the Gauḍīya Vaiṣṇava Sampradāya they become acquainted with the service of Śrī Rādhā.
After establishing the self-identification as Rādhā’s dāsī, they continue their bhajana according to the love of rādhā snehādhikā (greater love for Rādhā than for Kṛṣṇa).
How enchanting it is to think of oneself: “I am Rādhā’s fallen maidservant!”

My bhajana is disturbed by bodily consciousness; my life is contaminated by all kinds of external behaviour!
Śrī Jīva Gosvāmī says: “What to speak of internally, even externally, while following the process of hearing, chanting and deity-worship, one should think of oneself as Rādhā’s maidservant.”
This is the bhūta-śuddhi (spiritual self-identification) of the Gauḍīya Vaiṣṇavas.

atha teṣāṁ śuddha bhaktānāṁ bhūta-śuddhyādikaṁ yathāmatir vyākhyāyate. tatra bhūta-śuddhir nijābhilaṣita bhagavat sevaupayika tat pārṣada-deha bhāvanā paryantaiva tat sevaika puruṣārthibhiḥ kāryā nijānukūlyāt (Bhakti Sandarbhaḥ – 286)

“Here the bhūta śuddhih of the pure devotees is explained. This means thinking of one’s own desired spiritual body, in which one associates with the Lord and which is suitable for serving Him. The real bhūta śuddhi for a pure devotee is to think himself in his own siddha svarūpa (spiritual body). This way of thinking is favorable for those who know that the highest goal of life is to serve God.”

Srila Ananta das Babaji