SB 5.1.6

yarhi vāva ha rājan sa rāja-putraḥ priyavrataḥ parama-bhāgavato nāradasya caraṇopasevayāñjasāvagata-paramārtha-satattvo brahma-satreṇa dīkṣiṣyamāṇo ’vani-tala-paripālanāyāmnāta-pravara-guṇa-gaṇaikānta-bhājanatayā sva-pitropāmantrito bhagavati vāsudeva evāvyavadhāna-samādhi-yogena samāveśita-sakala-kāraka-kriyā-kalāpo naivābhyanandad yadyapi tad apratyāmnātavyaṁ tad-adhikaraṇa ātmano ’nyasmād asato ’pi parābhavam anvīkṣamāṇaḥ.
Word for word: 
yarhi — because; vāva ha — indeed; rājan — O King; saḥ — he; rāja-putraḥ — the Prince; priyavrataḥ — Priyavrata; parama — supreme; bhāgavataḥ — devotee; nāradasya — of Nārada; caraṇa — the lotus feet; upasevayā — by serving; añjasā — quickly; avagata — became aware of; parama-artha — transcendental subject matter; sa-tattvaḥ — with all knowable facts; brahma-satreṇa — by continuous discussion of the Supreme; dīkṣiṣyamāṇaḥ — desiring to fully dedicate himself; avani-tala — the surface of the globe; paripālanāya — to rule over; āmnāta — directed in the revealed scriptures; pravara — highest; guṇa — of qualities; gaṇa — the sum total; ekānta — without deviation; bhājanatayā — because of his possessing; sva-pitrā — by his father; upāmantritaḥ — being asked; bhagavati — in the Supreme Personality of Godhead; vāsudeve — the all-pervading Lord; eva — certainly; avyavadhāna — without cessation; samādhi-yogena — by practicing yoga in complete absorption; samāveśita — completely dedicated; sakala — all; kāraka — senses; kriyā-kalāpaḥ — whose total activities; na — not; eva — thus; abhyanandat — welcomed; yadyapi — although; tat — that; apratyāmnātavyam — not to be rejected for any reason; tat-adhikaraṇe — in occupying that post; ātmanaḥ — of himself; anyasmāt — by other engagements; asataḥ — material; api — certainly; parābhavam — deterioration; anvīkṣamāṇaḥ — foreseeing.
Translation: 
Śukadeva Gosvāmī continued: My dear King, Prince Priyavrata was a great devotee because he sought the lotus feet of Nārada, his spiritual master, and thus achieved the highest perfection in transcendental knowledge. With advanced knowledge, he always engaged in discussing spiritual subjects and did not divert his attention to anything else. The Prince’s father then asked him to take charge of ruling the world. He tried to convince Priyavrata that this was his duty as indicated in the revealed scriptures. Prince Priyavrata, however, was continuously practicing bhakti-yoga by constantly remembering the Supreme Personality of Godhead, thus engaging all his senses in the service of the Lord. Therefore, although the order of his father could not be rejected, the Prince did not welcome it. Thus he very conscientiously raised the question of whether he might be diverted from devotional service by accepting the responsibility of ruling over the world.
Purport: 

Śrīla Narottama dāsa Ṭhākura has sung, chāḍiyā vaiṣṇava-sevā nistāra pāyeche kebā: “Without serving the lotus feet of a pure Vaiṣṇava or spiritual master, no one has ever attained perfect liberation from material bondage.” Prince Priyavrata regularly served the lotus feet of Nārada, and thus the Prince perfectly understood transcendental subjects in truth (sa-tattvaḥ). The word sa-tattvaḥ means that Priyavrata knew all the facts about the spirit soul, the Supreme Personality of Godhead, and the relationship between the spirit soul and the Supreme Personality of Godhead and he also knew all about this material world and the relationship of the spirit soul and the Supreme Lord within the material world. Thus the Prince decided to engage himself only in rendering service to the Lord.

When Priyavrata’s father, Svāyambhuva Manu, requested him to accept the responsibility of ruling over the world, he did not welcome the suggestion. This is the symptom of a great, liberated devotee. Even though engaged in worldly affairs, he does not take pleasure in them, but remains always absorbed in the Lord’s service. While thus serving the Lord, he deals externally with worldly affairs without being affected. For example, although he has no attraction for his children, he cares for them and educates them to become devotees. Similarly, he speaks to his wife with affectionate words, but he is not attached to her. By rendering devotional service, a devotee acquires all the good qualities of the Supreme Lord. Lord Kṛṣṇa had sixteen thousand wives, all of them very beautiful, and although He dealt with each of them as a beloved husband, He was not attracted or attached to any of them. In the same way, although a devotee may enter family life and act very affectionately toward his wife and children, he is never attached to these activities.

This verse states that by serving the lotus feet of his spiritual master, Prince Priyavrata very soon attained the perfectional stage of Kṛṣṇa consciousness. This is the only way to advance in spiritual life. As stated in the Vedas:

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

“If one has unflinching faith in the Supreme Lord and the spiritual master, the essence of all Vedic knowledge is revealed to him. (Śvetāśvatara Upaniṣad 6.23) A devotee always thinks of the Lord continuously. While chanting the Hare Kṛṣṇa mantra, the words Kṛṣṇa and Hare immediately remind him of all the Lord’s activities. Since his entire life is engaged in the service of the Lord, a devotee cannot forget the Lord at any time. Just as an ordinary man always engages his mind in material activities, a devotee always engages his mind in spiritual activities. This is called brahma-satra, or meditating upon the Supreme Lord always. Prince Priyavrata was perfectly initiated into this practice by Śrī Nārada.