Swami Vivekananda's illuminative ideas on religion are spread over nearly 4200 pages of his Complete Works. This book containing eight lectures is a compilation from the same and serves as a small introduction to his voluminous writings, talks, and lectures on the subject.
Those who work at a thing heart and soul not only achieve success in it but through their absorption in that they also realize the supreme truth -- Brahman. Those who work at a thing with their whole heart receive help from God.
-Swami Vivekananda