In the matter of devotion to the Supreme Lord, faith is the primary component that must be there. In all the scriptures, blind faith is not respected. But faith that is supported by proper understanding of scriptural knowledge is very essential. Srila Bhaktivinoda Thakura says that sraddha, or faith, is the only rule for those who are established in the level of bhakti, or devotion. So, our acaryas have analyzed that the nine stages of bhakti -- from the very beginning stage of sraddha to the highest stage of prema -- are nothing but transformations of different stages of faith. Preliminary faith (sraddha) is nurtured through the association of saintly persons (sadhu-sanga) to the point at which one takes to the practices of devotion (bhajana kriya), and then with increased faith one tries to remove obstacles in the path of devotion (anartha-nvritti). When faith becomes very firm and fixed (nista), then one gets deeper taste (ruci) and ecstasy (bhava) in spiritual life and at last achieves the final stage of full blown prema. All those stages are nothing but a continuum of blossoming of one's faith.
Faith is something that is inherent or intrinsic to the soul. Bhaktivinoda Thakura reasons in his writings that the life of faith is enthusiasm. By that he means that if someone says they have faith in God but they do not act on that faith, then it is meaningless. Those are just some words that have no impact, effect, or meaning. Faith is the essence of spiritual life, and enthusiasm is the life of faith. If we act with enthusiasm based upon faith that is coming through the standard scriptures in proper direction, or when one has faith that is carefully considered and directed by scriptural authorities, then very quickly the obstacles and offenses in the spiritual path are removed.
-- From a lecture by HH Romapada Swami on 'Bhaktyaloka', delivered on 25th May 2003 in Chicago, US.