It is said that the transcendental name, form, quality, pastimes, paraphernalia, personality, etc., cannot possibly be perceived by the gross materialistic senses. But when the senses are purified by the process of hearing, chanting, remembering, and worshiping the lotus feet of the holy Deity, etc., the Lord reveals Himself proportionately to the advancement of the quality of devotional service (ye yathā māṁ prapadyante (B.G.4:11)). One should not expect the Lord to be an order-supplying agent who must be present before us as soon as we desire to see Him. We must be ready to undergo the prescribed devotional duties, following the path shown by the predecessors in the disciplic succession from Brahmā, Nārada and similar authorities. As the senses are progressively purified by bona fide devotional service, the Lord reveals His identity according to the spiritual advancement of the devotee. But one who is not in the line of devotional service can hardly perceive Him simply by calculations and philosophical speculations. Such a hard worker can present a jugglery of words before an audience, but can never know the Supreme Personality of Godhead in His personal feature. The Lord has clearly stated in the Bhagavad-gītā that one can know Him only by devotional service. No one can know the Lord by any puffed-up material process of challenge, but the humble devotee can please the Lord by his earnest devotional activities.
(Srimad Bhagavatam-2:6:38-purport).

The troubles of penance accepted by Lord Brahmā were certainly in the line of devotional service (bhakti). Otherwise there was no chance that Vaikuṇṭha or svalokam, the Lord's personal abodes, would become visible to Brahmājī. The personal abodes of the Lord, known as Vaikuṇṭhas, are neither mythical nor material, as conceived by the impersonalists. But realization of the transcendental abodes of the Lord is possible only through devotional service, and thus the devotees enter into such abodes. There is undoubtedly trouble in executing penance. But the trouble accepted in executing bhakti-yoga is transcendental happiness from the very beginning, whereas the trouble of penance in other processes of self-realization (jñāna-yoga, dhyāna-yoga, etc.), without any Vaikuṇṭha realization, ends in trouble only and nothing more. There is no profit in beating husks without grains. Similarly, there is no profit in executing troublesome penances other than bhakti-yoga for self-realization.
(Srimad Bhagavatam-2:9:9-purport).

King Kulaśekhara, an ideal pure devotee of the Lord, shows us by his own realization how to offer prayers to the Lord. Since he is a mahā-jana, an authority in the line of devotional service, it is our prime duty to follow in his footsteps in order to achieve the highest devotional platform.
(Mukunda-Mala-Stotra mantra1-purport).

In the stage of perfection, one's heart becomes slackened and one becomes more and more attached to attaining the lotus feet of the Lord. Śrīla Rūpa Gosvāmī, a great ācārya in the line of devotional service, has described this stage as follows: "Although appearing just like a madman, a person in the ecstasy of devotional service is not mad in the material conception of the term; this ecstasy is the manifestation of the pleasure potency of the Supreme Lord." The Lord has various potencies, one of which is called āhlādinī-śakti, His internal pleasure potency. Only one who becomes a little conversant with this potency can taste such ecstasy. The Vedānta-sūtra (1.1.12) states, ānanda-mayo 'bhyāsāt: "By nature the Lord is always joyful." This joyfulness of the Lord is due to His pleasure potency.
(Narada Bhakti Sutra 6-purport).