Brahmanas should preach

[Bhakti Vikasa Swami]

A brahmana who is born out of the head of the Lord has as his business to
preach the transcendental Vedic sounds, or sabda-brahma. Because the brahmana
is the head, he has to preach the transcendental sound, and he also has to eat
on behalf of the Supreme Lord. According to Vedic injunctions, when a brahmana
eats it is to be understood that the Personality of Godhead is eating through
him. It is not, however, that the brahmana should simply eat on behalf of the
Lord and not preach the message of the Bhagavad-gita to the world. Actually,
one who preaches the message of the Gita is very dear to Krsna, as is confirmed
in the Gita itself. Such a preacher is factually a brahmana.
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From The Nectar of Devotion ch. 2
by Srila Prabhupada