One can achieve the seed of bhakti-lata, devotional service, by the mercy of guru and Krsna. The duty of the guru is to find the means, according to the time, the circumstances and the candidate, by which one can be induced to render devotional service, which Krsna accepts from a candidate who wants to be successful in going back home, back to Godhead. After wandering throughout the universe, a fortunate person within this material world seeks shelter of such a guru, or acarya, who trains the devotee in the suitable ways to render service according to the circumstances so that the Supreme Personality of Godhead will accept the service. This makes it easier for the candidate to reach the ultimate destination. The acaryas duty, therefore, is to find the means by which devotees may render service according to references from sastra. Rupa Gosvami, for example, in order to help subsequent devotees, published such devotional books as Bhakti-rasamrta-sindhu. Thus it is the duty of the acarya to publish books that will help future candidates take up the method of service and become eligible to return home, back to Godhead, by the mercy of the Lord. In our Krsna consciousness movement, this same path is being prescribed and followed. Thus the devotees have been advised to refrain from four sinful activitiesillicit sex, intoxication, meat-eating and gamblingand to chant sixteen rounds a day. These are bona fide instructions. Because in the Western countries constant chanting is not possible, one should not artificially imitate Haridasa Thakura, but should follow this method. Krsna will accept a devotee who strictly follows the regulative principles and the method prescribed in the various books and literatures published by the authorities. The acarya gives the suitable method for crossing the ocean of nescience by accepting the boat of the Lords lotus feet, and if this method is strictly followed, the followers will ultimately reach the destination, by the grace of the Lord. This method is called acarya-sampradaya. It is therefore said, sampradaya-vihina ye mantras te nisphala matah (Padma Purana). The acarya-sampradaya is strictly bona fide. Therefore one must accept the acarya-sampradaya; otherwise ones endeavor will be futile. Srila Narottama dasa Thakura therefore sings:

One must worship the lotus feet of the acarya and live within the society of devotees. Then ones endeavor to cross over nescience will surely be successful.