SB 7.10.40

yathā yathā bhagavato
 bhaktyā paramayābhidā
nṛpāś caidyādayaḥ sātmyaṁ
 hares tac-cintayā yayuḥ
Word for word: 
yathā yathā — just as; bhagavataḥ — of the Supreme Personality of Godhead; bhaktyā — by devotional service; paramayā — supreme; abhidā — incessantly thinking of such activities; nṛpāḥ — kings; caidya-ādayaḥ — Śiśupāla, Dantavakra and others; sātmyam — the same form; hareḥ — of the Supreme Personality of Godhead; tat-cintayā — by constantly thinking of Him; yayuḥ — returned home, back to Godhead.
Translation: 
By devotional service, pure devotees who incessantly think of the Supreme Personality of Godhead receive bodies similar to His. This is known as sārūpya-mukti. Although Śiśupāla, Dantavakra and other kings thought of Kṛṣṇa as an enemy, they also achieved the same result.
Purport: 

In Caitanya-caritāmṛta, in connection with Lord Caitanya’s instructions to Sanātana Gosvāmī, it is explained that a devotee should externally execute his routine devotional service in a regular way but should always inwardly think of the particular mellow in which he is attracted to the service of the Lord. This constant thought of the Lord makes the devotee eligible to return home, back to Godhead. As stated in Bhagavad-gītā (4.9), tyaktvā dehaṁ punar janma naiti mām eti: after giving up his body, a devotee does not again receive a material body, but goes back to Godhead and receives a spiritual body resembling those of the Lord’s eternal associates whose activities he followed. However the devotee likes to serve the Lord, he may constantly think of the Lord’s associates — the cowherd boys, the gopīs, the Lord’s father and mother, His servants and the trees, land, animals, plants and water in the Lord’s abode. Because of constantly thinking of these features, one acquires a transcendental position. Kings like Śiśupāla, Dantavakra, Kaṁsa, Pauṇḍraka, Narakāsura and Śālva were all similarly delivered. This is confirmed by Madhvācārya:

pauṇḍrake narake caiva
 śālve kaṁse ca rukmiṇi
āviṣṭās tu harer bhaktās
 tad-bhaktyā harim āpire

Pauṇḍraka, Narakāsura, Śālva and Kaṁsa were all inimical toward the Supreme Personality of Godhead, but because all these kings constantly thought of Him, they achieved the same liberation — sārūpya-mukti. The jñāna-bhakta, the devotee who follows the path of jñāna, also attains the same destination. If even the enemies of the Lord achieve salvation by constantly thinking about the Lord, what is to be said of pure devotees who always engage in the Lord’s service and who think of nothing but the Lord in every activity?