One will not derive the benefit by rendering service to false Brahmana.

In Bhagavad-gita (2.65) it is said: prasade sarva-duhkhanam hanir asyopajayate. Unless one is self-satisfied, he cannot be free from the miserable conditions of material existence. Therefore it is essential to render service to the Brahmanas and Vaisnavas to achieve the perfection of self-satisfaction. Srila Narottama Dasa Thakura therefore says:

tandera carana sevi bhakta-sane vasa janame janame haya, ei abhilasa

“Birth after birth I desire to serve the lotus feet of the acaryas and live in a society of devotees.” A spiritual atmosphere can be maintained only by living in a society of devotees and by serving the orders of the acaryas. The spiritual master is the best brahmana. At present, in the age of Kali, it is very difficult to render service to the brahmana-kula, or the brahmana class. The difficulty, according to the Varaha Purana, is that demons, taking advantage of Kali-yuga, have taken birth in brahmana families. Raksasah kalim asritya jayante brahma-yonisu (Varaha Purana). In other words, in this age, there are many so-called caste Brahmanas and caste Gosvamis who, taking advantage of the sastra and of the innocence of people in general, claim to be Brahmanas and Vaisnavas by hereditary right. One will not derive any benefit by rendering service to such false brahmana-kulas. One must, therefore, take shelter of a bona fide spiritual master and his associates and should also render service to them, for such activity will greatly help the neophyte in attaining full satisfaction. This has been very clearly explained by Srila Visvanatha Cakravarti Thakura in his explanation of the verse vyavasayatmika buddhir ekeha kuru-nandana (Bg. 2.41). By actually following the regulative principles of bhakti-yoga as recommended by Srila Narottama Dasa Thakura, one can very quickly come to the transcendental platform of liberation, as explained in this verse (atyanta-samam).

The particular use of the word anativelam (“without delay”) is very significant because simply by serving Brahmanas and Vaisnavas one can get liberation. There is no need to undergo severe penances and austerities. The vivid example of this is Narada Muni himself. In his previous birth, he was simply a maidservant’s son, but he got the opportunity to serve exalted Brahmanas and Vaisnavas, and thus in his next life he not only became liberated but became famous as the supreme spiritual master of the entire Vaisnava disciplic succession. According to the Vedic system, therefore, it is customarily recommended that after performing a ritualistic ceremony, one should feed the Brahmanas.

Source: A .C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Fourth Canto, Chapter 21 – Text 40