ततो जगन्मङ्गलमच्युतांशंसमाहितं शूरसुतेन देवी । दधार सर्वात्मकमात्मभूतंकाष्ठा यथानन्दकरं मनस्त: ॥ १८ ॥
tato jagan-maṅgalam acyutāṁśaṁ samāhitaṁ śūra-sutena devī dadhāra sarvātmakam ātma-bhūtaṁ kāṣṭhā yathānanda-karaṁ manastaḥ
Thereafter, by Śūrasuta Vasudeva, the all-auspicious, fully opulent Bhagavān—Acyuta with His plenary expansions—was transferred from Vasudeva’s mind to Devakī’s mind. Thus initiated by Vasudeva, Devakī bore Śrī Kṛṣṇa within the core of her heart—He who is the original consciousness of all and the cause of all causes—and she became beautiful like the eastern horizon adorned by the rising moon.
As indicated here by the word manastaḥ, the Supreme Personality of Godhead was transferred from the core of Vasudeva’s mind or heart to the core of the heart of Devakī. We should note carefully that the Lord was transferred to Devakī not by the ordinary way for a human being, but by dīkṣā, initiation. Thus the importance of initiation is mentioned here. Unless one is initiated by the right person, who always carries within his heart the Supreme Personality of Godhead, one cannot acquire the power to carry the Supreme Godhead within the core of one’s own heart.
It says Devakī conceived the Lord’s infallible plenary portion, who is the auspiciousness of the whole universe and the Supersoul of all beings.
Because Vasudeva is the son of Śūra (a Yādava chief), and the verse notes that Devakī’s mind became steady through him as she conceived the Lord.
It teaches that when the mind becomes steady and surrendered, the Lord—who is the inner Self of all—reveals His auspicious presence and brings deep joy to the heart.