Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 9

Sanskrit:

वीक्ष्य तत् कदनं स्वानां निरूप्य पुररक्षणम् ।सौभं च शाल्वराजं च दारुकं प्राह केशव: ॥ ९ ॥

ITRANS:

vīkṣya tat kadanaṁ svānāṁnirūpya pura-rakṣaṇamsaubhaṁ ca śālva-rājaṁ cadārukaṁ prāha keśavaḥ

Translation:

[Śukadeva Gosvāmī continued:] After He arrived at Dvārakā and saw how His people were threatened with destruction, and also saw Śālva and his Saubha airship, Lord Keśava arranged for the city’s defense and then addressed Dāruka as follows.

Purport:

Lord Kṛṣṇa placed Śrī Balarāma in a strategic position to guard the city, and He also appointed a special guard for Śrī Rukmiṇī and the other queens inside the palaces. According to Śrīla Viśvanātha Cakravartī, by a secret route special soldiers conveyed the queens to safety inside Dvārakā.