Anyone, even a person in an impure state, who absorbs his mind in Lord Krishna for just a moment at the time of death burns up all traces of sinful reactions and immediately attains the supreme transcendental destination in a pure, spiritual form as effulgent as the sun.
Speculative knowledge alone, without devotional service, is not able to give liberation. On the other hand, even without knowldege one can obtain liberation if one engages in the Lord's devotional service. — Sri Chaitanya Caritamrita, Madhya Lila, 22.21.
A man bound by the hands and feet cannot free himself. He must be helped by a person who is unbound because the bound cannot help the bound, the rescuer must be liberated. Therefore, only Lord Krishna or His bona fide representative can release the conditioned soul.
sprhayami na muktaye
bhavan prabhur aham
dasa iti yatra vilupyate
I do not wish to take liberation or to merge in the Brahman effulgence, where the conception of being a servant of the Lord is completely lost.
Sri Chaitanya Caritamrita Adi Lila 6.42,
A Vaishnava bestows the priceless gift of the mahamantra, Hare Krishna Hare Krishna Krishna Krishna Hare Hare/ Hare Rama Hare Rama Rama Rama Hare Hare. Simply by chainting this mantra one can remain in a liberated state.
The Matchless gift, Chapter-7,
Pure devotees, who take transcendental pleasure in hearing and chanting the glories of the Lord, do not care for any kind of liberation; even if they are offered the five liberations, they refuse to accept them