Due to King Pratāparudra’s firm determination, the Bhaṭṭācārya predicted that the King would receive Śrī Caitanya Mahāprabhu’s mercy without fail. As confirmed elsewhere in Caitanya-caritāmṛta (Madhya 19.151), guru-kṛṣṇa-prasāde pāya bhakti-latā-bīja: “By the mercy of the spiritual master and Kṛṣṇa, one gets the seed of devotional service.” The Bhaṭṭācārya was the spiritual master of King Pratāparudra, and he gave his blessings to the effect that the Lord would be merciful upon the King. The mercy of the spiritual master and Kṛṣṇa combine to grant success to a devotee engaged in Kṛṣṇa consciousness. This is confirmed by the Vedas:

yasya deve parā bhaktir yathā deve tathā gurau
tasyaite kathitā hy arthāḥ prakāśante mahātmanaḥ

“Only unto those great souls who have implicit faith in both the Lord and the spiritual master are all the imports of Vedic knowledge automatically revealed.” (Śvetāśvatara Upaniṣad 6.23)

Mahārāja Pratāparudra had firm faith in the Bhaṭṭācārya, who declared Śrī Caitanya Mahāprabhu to be the Supreme Personality of Godhead. Having firm faith in the Bhaṭṭācārya as his spiritual master, King Pratāparudra immediately accepted Śrī Caitanya Mahāprabhu as the Supreme Lord. Thus he began worshiping Śrī Caitanya Mahāprabhu in his mind. This is the process of devotional service. According to Lord Kṛṣṇa in the Bhagavad-gītā (9.34):

man-manā bhava mad-bhakto mad-yājī māṁ namaskuru
mām evaiṣyasi yuktvaivam ātmānaṁ mat-parāyaṇaḥ

“Engage your mind always in thinking of Me, become My devotee, offer obeisances to Me and worship Me. Being completely absorbed in Me, surely you will come to Me.”

This process is very simple. One need only be firmly convinced by the spiritual master that Kṛṣṇa is the Supreme Personality of Godhead. If one decides this, he can make further progress by thinking of Kṛṣṇa, chanting of Kṛṣṇa and glorifying Him. There is then no doubt that such a fully surrendered devotee will receive the blessings of Lord Kṛṣṇa. Śrīla Sārvabhauma Bhaṭṭācārya explains this further.