A devotee is one who has recovered his intelligence and sanity. Thus he avoids sin, just as an intelligent child or sane person avoids touching fire.
Guru is not on the way to Krishna, Guru is 'the way' to Krishna.
Four 'R's of Krishna Consciousness: Recognition (locating the weeds inside the heart), Remorse (feeling ashamed of them), Rectification (removing the weeds from the heart) and Reunion (Krishna awarding us His love).
If an ordinary man does not eat, he will grow weak and die. Similarly, if a devotee does not taste the transcendental pastimes of Lord Chaitanya Mahaprabhu and Lord Krishna, he will gradually weaken and die spiritually.