It is not possible for a conditioned soul to directly meet Krishna, the Supreme Personality of Godhead, but if one becomes a sincere devotee and seriously engages in devotional service, Lord Krishna sends an instructing spiritual master to show him favor and invoke his dormant propensity for serving the Supreme. The preceptor appears before the external senses of the fortunate conditioned soul, and at the same time the devotee is guided from within by the caittya-guru, Krishna, who is seated as the spiritual master within the heart of the living entity.
His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
Sri Chaitanya-charitamrita, Adi-lila 1.58, Purport

Anything done as sacrifice, charity, or penance without faith in the Supreme, O son of Pritha, is impermanent. It is called asat and is useless both in this life and the next.
Lord Sri Krishna
Bhagavad-gita 17.28

O my Lord [Krishna], may I have the association of Your devotees, which is a sharp sword that cuts the bonds of repeated birth and death and is the only way to attain a place at Your lotus feet. Please give me devotional service to Your lotus feet birth after birth.
Sri Yamaraja
Brahma-vaivarta Purana 4.6.24

O King, as I remember the wonderful form of Lord Krishna, I am struck with wonder more and more, and I rejoice again and again.
Sri Sanjaya
Bhagavad-gita 18.77

Whenever pure topics of the transcendental world are discussed, the members of the audience forget all kinds of material hankerings, at least for the time being. Not only that, but they are no longer envious of one another, nor do they suffer from anxiety or fear.
The Pracetas
Srimad-Bhagavatam 4.30.35

The desire to gratify one’s own senses is kama [lust], but the desire to please the senses of Lord Krishna is prema [love].
Srila Krishnadasa Kaviraja Goswami
Sri Chaitanya-charitamrita, Adi-lila 4.165

Whatever is in Krishna is in His holy name, for the two are nondifferent. The name is eternally free from material contamination and spiritually situated in a state of pure goodness (shuddha-sattva) like Krishna. Though descending into the material world, the name remains pure, eternal, and the embodiment of the highest sweetness (rasa).
Srila Haridasa Thakura
Sri Harinama Cintamani, Chapter 2

Although Vaishnavas appear in poor families within this world to teach the fallen and wretched living entities to worship Hari [Krishna], they are not actually poor. The purpose of such pastimes is to demonstrate how one can worship Hari in spite of being born in a poor family. The characteristics of Vaishnavas are incomprehensible to the materialists.
Srila Bhaktisiddhanta Sarasvati Thakura
Sri Chaitanya-bhagavata Madha-khanda, Chapter 9, Summary