The Lord lives in the spiritual world in His original personality, and a devotee who follows the instructions of the Lord approaches Him (mameti). As a spiritual person, such a devotee returns to the Personality of Godhead and plays and dances with Him. That is the ultimate goal of life. – His Divine Grace A. C. Bhaktivedanta Swami Prabhupada Srimad-Bhagavatam 8.24.51, Purport

When one’s peaceful consciousness, strengthened by the mode of goodness, is fixed on the Personality of Godhead, one achieves religiosity, knowledge, detachment, and opulence.- Lord Sri Krishna Srimad-Bhagavatam 11.19.25

When Hari [Krishna], the Lord of all demigods and heavenly residents, is duly worshiped by means of maha-mantras composed of His holy names, the ghost like sins can no longer exist.- Padma Purana, Svarga-khanda 50.6

I am drowning in the ocean of birth and death. The fish of my mind is trapped in the horrible narrow well of repeated birth and death. O Lord, please rescue me from this horrible world of birth and death and give me loving devotion for Your lotus feet.- Lord Siva Brahma-vaivarta Purana 4.6.23

Sri-nama-sankirtana [the chanting of the holy names of the Lord] is the best sadhana [spiritual practice]. If other sadhanas help us in Krishna-sankirtana, then they deserve to be called sadhana; otherwise they are simply impediments to sadhana. Sri-Krishna-nama-sankirtana is the emperor of sadhanas. It is the only infallible sadhana capable of bringing us to siddhi [spiritual perfection]. – Srila Bhaktisiddhanta Sarasvati Thakura Sri Srila Prabhupader Upadesamrta, p. 274

One should associate with devotees, chant the holy name of the Lord, hear Srimad-Bhagavatam, reside at Mathura [Vrindavana], and worship the deity with faith and veneration. These five limbs of devotional service are the best of all. Even a slight performance of these five awakens love for Krishna.- Sri Caitanya Mahaprabhu Sri Caitanya-caritamrta, Madhya-lila 22.128–129

One should not hear anything about Krishna from a non-Vaishnava. Milk touched by the lips of a serpent has poisonous effects; similarly, talks about Krishna given by a non-Vaishnava are also poisonous.- Srila Sanatana Gosvami Hari-bhakti-vilasa (quoting Padma Purana)