BG Chap 14 - Attaining Brahman
Why one practicing pure devotional service would attain the impersonal Brahman? Kṛṣṇa answers that He is the basis (pratiṣṭha) of impersonal Brahman. He is the supreme basis of everything. He is the basis of immortal nectar (amṛtasya), which is not the nectar of Svarga, because that nectar is not immortal. The immortal nectar (avyayasya) refers to liberation. Kṛṣṇa is the basis of the eternal method of dharma (śāśvatasya dharmasya), which is eternally present both in the stage of sādhana and the stage of perfection. This supreme method is bhakti. He is also the basis of extraordinary happiness (sukhasya), which is prema in relation to the ekāntika devotee (aikāntikasya), who is qualified to receive it. If one worships the Lord with a desire to merge into Him, Kṛṣṇa being the basis of everything, would grant such a desire. Just as the sun is the intensified form of light and also is the basis of light, Kṛṣṇa is the concentrated form of Brahman and the basis of Brahman. Thus the devotee does not merely attain Brahman but Kṛṣṇa, who is alone the end, the conclusion and the completeness of Brahman.
Why should a person take shelter of the Lord once he is liberated, as liberation is the final result? Kṛṣṇa alone is the shelter (pratiṣṭha) of the six eternal (śāśvatasya) qualities called ṣaḍ-aiśvarya (dharmasya). He alone is the shelter of His extraordinary (ekāntikasya) rasa (sukhasya) arising from variegated pastimes. The devotee takes shelter of Kṛṣṇa alone for experiencing His intensely blissful form, its astounding qualities and His pastimes. Attaining Him, the embodiment of rasa, one becomes blissful.