The word bhagavad-dharmiṇaḥ indicates that the religious process practiced by Mahārāja Pṛthu was beyond all pretensions. As stated in the beginning of Śrīmad-Bhāgavatam (1.1.2) , dharmaḥ projjhita-kaitavo ’tra: religious principles which are simply pretentious are actually nothing but cheating. Bhagavad-dharmiṇaḥ is described by Vīrarāghava Ācārya as nivṛtta-dharmeṇa, which indicates that it cannot be contaminated by material aspiration. As described by Śrīla Rūpa Gosvāmī:

anyābhilāṣitā-śūnyaṁ jṣāna-karmādy-anāvṛtam ānukūlyena kṛṣṇānu- śīlanaṁ bhaktir uttamā

When one who is not inspired by material desires and is not contaminated by the processes of fruitive activity and empiric speculation fully engages in the favorable service of the Lord, his service is called bhagavad-dharma, or pure devotional service. In this verse the word brahmaṇi does not refer to the impersonal Brahman. Impersonal Brahman is a subordinate feature of the Supreme Personality of Godhead, and since impersonal Brahman worshipers desire to merge into the Brahman effulgence, they cannot be considered followers of bhagavad-dharma. After being baffled in his material enjoyment, the impersonalist may desire to merge into the existence of the Lord, but a pure devotee of the Lord has no such desire. Therefore a pure devotee is really bhagavad-dharmī.

It is clear from this verse that Mahārāja Pṛthu was never a worshiper of the impersonal Brahman but was at all times a pure devotee of the Supreme Personality of Godhead. Bhagavati brahmaṇi refers to one who is engaged in devotional service to the Personality of Godhead. A devotee’s knowledge of the impersonal Brahman is automatically revealed, and he is not interested in merging into the impersonal Brahman. Mahārāja Pṛthu’s activities in devotional service enabled him to become fixed and steady in the discharge of devotional activities without having to take recourse to karma, jṣāna or yoga.