One must execute devotional service under the guidance of a devotee or directly under the guidance of the Supreme Personality of Godhead. It is not possible, however, to train oneself without guidance from the spiritual master.
A. C. Bhaktivedanta Swami PrabhupadaA grain of devotion is more valuable thank tons of faithlessness.
A. C. Bhaktivedanta Swami PrabhupadaThe artist draws a picture of a rose very nicely with all attention and artistic sense, and yet it does not become as perfect as the real rose. If that is the real fact, how can we say that the real rose has taken its shape without Intelligence behind the beauty?
A. C. Bhaktivedanta Swami PrabhupadaThe holy name of Krishna has extraordinary spiritual potency because the name of God is nondifferent from God Himself.
A. C. Bhaktivedanta Swami PrabhupadaIt is said about Lord Buddha sadaya-hrdaya darsita-pasu-ghatam. He saw the whole human race going to hell by this animal killing. So he appeared to teach ahimsa, nonviolence, being compassionate on the animals and human beings. In the Christian religion also, it is clearly stated, 'Thou shall not kill'. So everywhere animal killing is restricted. In no religion the unnecessary killing of animals is allowed. But nobody is caring. The killing process is increasing, and so are the reactions. Every ten years you will find a war. These are the reactions.
A. C. Bhaktivedanta Swami PrabhupadaThe spiritual master and Krishna are two parallel lines. The train, on two tracks, moves forward. The spiritual Master and Krishna are like these two tracks. They must be served simultaneously. Krishna helps one to find bona fide Spiritual Master and bona fide Spiritual Master helps one to understand Krishna. If one does not get bona fide Spiritual Master, then how he can ever understand Krishna ? You cannot serve Krishna without Spiritual Master, or serve just Spiritual Master without serving Krishna. They must be served simultaneously.
A. C. Bhaktivedanta Swami Prabhupada