The desire to merge into the impersonal Brahman is the subtlest type of atheism. As soon as such atheism, disguised in the dress of liberation, is encouraged, one becomes completely unable to traverse the path of devotional service to the Supreme Personality of Godhead.
His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
Sri Chaitanya-charitamrita, Adi-lila 1.92, Purport

Although the quality of being self-satisfied is eternally present in Krishna, the quality of enjoying pastimes is also eternally present in Him. For the Supreme Lord to possess contradictory characteristics in perfect harmony is natural. In one respect, Krishna has the quality of self-satisfaction, and in another respect, He manifests His opposite quality of enjoying pastimes with others.
Srila Bhaktivinoda Thakura
Sri Chaitanya-shikshamrita, Part 2

The highest devotion is attained by slow degrees by the method of constant endeavor for self-realization with the help of scriptural evidence, theistic conduct and perseverance in practice.
Lord Sri Krishna
Brahma-samhita 5.59

Accepting the bona fide spiritual master as one’s life and soul and worshipable deity, the disciple should learn from him the process of pure devotional service. The Supreme Personality of Godhead, Hari, the soul of all souls, is inclined to give Himself to His pure devotees. Therefore, the disciple should learn from the spiritual master to serve the Lord without duplicity and in such a faithful and favorable way that the Supreme Lord, being satisfied, will offer Himself to the faithful disciple.
Sri Prabuddha
Srimad-Bhagavatam 11.3.22

O Lord Mukunda! I bow down my head to Your Lordship and respectfully ask You to fulfill this one desire of mine: that in each of my future births I will, by Your Lordship’s mercy, always remember and never forget Your lotus feet.
King Kulashekhara
Mukunda-mala-stotra 3

The Supreme Lord is the Supreme Brahman, devoid of any connection with maya and without any transformation. He resides in the effulgent supreme abode beyond the material covering. The self-realized souls know Him to be the bright illumination of the sun.
Mundaka Upanishad 2.2.9

By showing mercy to all living entities, being satisfied somehow or other and controlling the senses from sense enjoyment, one can very quickly satisfy the Supreme Personality of Godhead, Janardana [“the Lord of all living entities”].
Sri Narada Muni
Srimad-Bhagavatam 4.31.19

The material desire to enjoy the material world and the desire to become liberated from material bondage are considered to be two witches, and they haunt one like ghosts. . . . As long as these two witches remain in the heart, there is no possibility of enjoying the transcendental bliss of devotional service.
Srila Rupa Goswami
Bhakti-rasamrita-sindhu 1.2.22