Mbh 12.165.1c

For this reason the energy of the Brahmanas can scarcely be borne or resisted by a king. The Brahmana is said to be creator, ruler, ordainer, and god. No word of abuse, no dry speeches, should be addressed to a Brahmana. The Kshatriya should cross all his difficulties by the aid of the might of his arms. The Vaisya and the Sudra should conquer their difficulties by wealth; the Brahmana should do so by Mantras and homa. None of these, viz., a maiden, a youthful woman, a person unacquainted with mantras, an ignorant guy, or one that is impure, is competent to pour libations on the sacrificial fire. If any of these do so, he or she is sure to fall into hell, with him for whom they act. For this reason, none but a Brahmana, conversant with the Vedas and skilled in all sacrifices should become the pourer of sacrificial libations. They who are conversant with the scriptures say that the man who, having kindled the sacrificial fire, does not give away the dedicated food as Dakshina, is not the kindler of a sacrificial fire. A person should, with his senses under control, and with proper devotion, do all the acts of merit (indicated in the scriptures). One should never worship the deities in sacrifices in which no Dakshina is given. A sacrifice not completed with Dakshina, (instead of producing merit) brings about the destruction of one's children, animals, and heaven. Such a sacrifice destroys also the senses, the fame, the achievements and the very span of life, that one has. Those Brahmanas that lie with women in their season, or who never perform sacrifices, or whose families have no members conversant with the Vedas, are regarded as Sudras in act. That Brahmana who, having married a Sudra girl, resides for twelve continuous years in a village has only a well for its water supply, becomes a Sudra in act.