He is at once raised to the platform of liberation, as stated in Bhagavad-gītā (14.26):
māṁ ca yo 'vyabhicāreṇa
bhakti-yogena sevate
sa guṇān samatītyaitān
brahma-bhūyāya kalpate
"One who engages in unalloyed devotional service to the Lord transcends the modes of material nature and is immediately elevated to the spiritual platform." A Kṛṣṇa conscious person begins from the transcendental stage, and he is constantly in that consciousness.
(Bhagavad-Gita----4:29----purport).

All different varieties of ātmārāmas (those who take pleasure in ātmā, or spirit self), especially those established on the path of self-realization, though freed from all kinds of material bondage, desire to render unalloyed devotional service unto the Personality of Godhead. This means that the Lord possesses transcendental qualities and therefore can attract everyone, including liberated souls."
(Srimad Bhagavatam----1:7:10----purport).

Unalloyed devotional service of the Lord progresses in different stages. Practice of devotional service in the material field is of eighty-one different qualities, and above such activities is the transcendental practice of devotional service, which is one and is called sādhana-bhakti. When unalloyed practice of sādhana-bhakti is matured into transcendental love for the Lord, the transcendental loving service of the Lord begins gradually developing into nine progressive stages of loving service under the headings of attachment, love, affection, feelings, affinity, adherence, following, ecstasy, and intense feelings of separation.
The attachment of an inactive devotee develops up to the stage of transcendental love of God. Attachment of an active servitor develops up to the stage of adherence, and that for a friendly devotee develops up to the stage of following, and the same is also the case for the paternal devotees. Devotees in conjugal love develop ecstasy up to the stage of intense feelings of separation. These are some of the features of unalloyed devotional service of the Lord.
(Srimad Bhagavatam----1:7:10----purport).

The Lord is the Supreme Father of all living beings, and therefore those who are conscious of this vital relation with God can make filial demands from the Father, and the Father is pleased to supply the demands of such obedient sons without bargaining. The Lord is just like the desire tree, and from Him everyone can have everything by the causeless mercy of the Lord. As the Supreme Father, the Lord, however, does not supply to a pure devotee what is considered to be a barrier to the discharge of devotional service. Those who are engaged in the devotional service of the Lord can rise to the position of unalloyed devotional service by His transcendental attraction.
(Srimad Bhagavatam----1:11:4-5----purport).

Absolute devotional service, conducted in nine different spiritual activities—hearing, chanting, remembering, worshiping, praying, etc.—does not always appeal to people with a pompous nature; they are more attracted by the Vedic superficial rituals and other costly performances of social religious shows. But the process according to the Vedic injunctions is that the fruits of all pious activities should be offered to the Supreme Lord. In Bhagavad-gītā (9.27), the Lord demands that whatever one may do in one's daily activities, such as worship, sacrifice, and offering charity, all the results should be offered to Him only. This offering of the results of pious acts unto the Supreme Lord is a sign of devotional service to the Lord and is of permanent value, whereas enjoying the same results for oneself is only temporary. Anything done on account of the Lord is a permanent asset and accumulates in the form of unseen piety for gradual promotion to the unalloyed devotional service of the Lord. These undetected pious activities will one day result in full-fledged devotional service by the grace of the Supreme Lord. Therefore, any pious act done on account of the Supreme Lord is also recommended here for those who are not pure devotees.
(Srimad Bhagavatam----3:9:13----purport).

Real jñāna means understanding that the living entity is the eternal servant of the Lord. This knowledge is attained after many, many births, as confirmed in Bhagavad-gītā (7.19): bahūnāṁ janmanām ante jñānavān māṁ prapadyate. In the paramahaṁsa stage of life, one fully realizes Kṛṣṇa as everything: vāsudevaḥ sarvam iti sa mahātmā sudurlabhaḥ. When one understands fully that Kṛṣṇa is everything and that Kṛṣṇa consciousness is the highest perfection of life, he becomes a paramahaṁsa, or mahātmā. Such a mahātmā or paramahaṁsa is very rare to find. A paramahaṁsa, or pure devotee, is never attracted by haṭha-yoga or speculative knowledge. He is simply interested in the unalloyed devotional service of the Lord. Sometimes one who was formerly addicted to these processes tries to perform devotional service and the jñāna and yoga practices at the same time, but as soon as one comes to the unalloyed stage of devotional service, he is able to give up all other methods of self-realization. In other words, when one firmly realizes Kṛṣṇa as the supreme goal, he is no longer attracted by mystic yoga practice or the speculative empirical methods of knowledge.
(Srimad Bhagavatam----4:23:12----purport).

"One who always engages in the spiritual activities of unalloyed devotional service at once transcends the modes of material nature and is elevated to the spiritual platform." The devotee is therefore above the three modes of material nature and is even transcendental to the brāhmaṇa platform. A brāhmaṇa may be infected by the two baser modes—namely rajo-guṇa and tamo-guṇa. A pure devotee, who is free from all material desires experienced on the mental platform and who is also free from empiric philosophical speculation or fruitive activity, is always above material conditioning and is always liberated.
(Srimad Bhagavatam----4:29:65----purport).

Only a rare person who has adopted complete, unalloyed devotional service to Kṛṣṇa can uproot the weeds of sinful actions with no possibility that they will revive. He can do this simply by discharging devotional service, just as the sun can immediately dissipate fog by its rays.
(Srimad Bhagavatam----6:1:15----translation).