In the Upaniṣads it is stated, nāyam ātmā bala-hīnena labhyaḥ. The purport is that one cannot attain the supreme platform of self-realization without being sufficiently favored by Balarāma. Bala does not mean physical strength. No one can attain spiritual perfection by physical strength. One must have the spiritual strength which is infused by Balarāma, or Saṅkarṣaṇa. Ananta, or Śeṣa, is the source of the power which sustains all the planets in their different positions. Materially this sustaining power is known as the law of gravitation, but actually it is a display of the potency of Saṅkarṣaṇa. Balarāma, or Saṅkarṣaṇa, is the source of spiritual power, or the original spiritual master. Therefore Lord Nityānanda Prabhu, who is also the incarnation of Balarāma, is the original spiritual master. And the spiritual master is the representative of Balarāma, the form of the Supreme Personality of Godhead who supplies spiritual strength. In the Caitanya-caritāmṛta it is confirmed that the spiritual master is the manifestation of the mercy of Kṛṣṇa.
Thus ordered by the Supreme Personality of Godhead, Yogamāyā circumambulated the Lord and then appeared within this material world according to His order. When Yogamāyā, the supreme power of the supremely powerful Personality of Godhead, transferred Lord Śeṣa from the womb of Devakī to the womb of Rohiṇī, both Devakī and Rohiṇī were under Yogamāyā’s spell, which is called yoga-nidrā. When this was done, people thought that Devakī’s seventh pregnancy had been a miscarriage. Thus although Balarāma appeared as the son of Devakī, He was transferred to the womb of Rohiṇī to appear as her son. After this arrangement, the Supreme Personality of Godhead, Kṛṣṇa, who is always ready to protect His unalloyed devotees, entered within the mind of Vasudeva as the Lord of the whole creation, with full inconceivable potencies. It is understood in this connection that Lord Kṛṣṇa first of all situated Himself in the unalloyed heart of Vasudeva and was then transferred to the heart of Devakī. He was not put into the womb of Devakī by seminal discharge. The Supreme Personality of Godhead, by His inconceivable potency, can appear in any way. It is not necessary for Him to appear in the ordinary way, by seminal injection within the womb of a woman.
When Vasudeva was sustaining the form of the Supreme Personality of Godhead within his heart, he appeared just like the glowing sun, whose shining rays are always unbearable and scorching to the common man. The form of the Lord situated in the pure unalloyed heart of Vasudeva is not different from the original form of Kṛṣṇa. The appearance of the form of Kṛṣṇa anywhere, and specifically within the heart, is called dhāma. Dhāma refers not only to Kṛṣṇa’s form but also to His name, His qualities and His paraphernalia. Everything becomes manifest simultaneously.
Thus the eternal form of the Supreme Personality of Godhead with full potencies was transferred from the mind of Vasudeva to the mind of Devakī, exactly as the setting sun’s rays are transferred to the full moon rising in the east.