The whole problem is they are not following the regulative principles, that I can detect. Without this, enthusiasm will be lacking. Even mechanically following, and if he gets gradually understanding from the class, he will come to the point of spontaneous enthusiasm. This spontaneous loving devotional service is not so easy matter, but if one simply sticks strictly to the rules and regulations, like rising early, chanting 16 rounds, chanting gayatri, keeping always clean - then his enthusiasm will grow more and more, and if there is also patience and determination, one day he will come to the platform of spontaneous devotion, then his life will be perfect.
Letter to Karandhara, 22 December, 1972