One must not only have the qualities of a brahmana, but one should also work as a brahmana, for one’s qualities are tested by his work. If one is a qualified engineer but simply sits down at home and does not work, what is his value? Similarly, unless one works as a brahmana, there is no value to his simply saying, “I am a brahmana.” One must therefore work as a brahmana by fully engaging in the service of Param Brahman, Krsna, the Supreme Brahman.

From: Krsna Consciousness, the Matchless Gift, by Srila Prabhupada