Mbh 12.89.1a

"'Bhishma said, "Let not such trees as yield edible fruits be cut down in thy dominions. Fruits and roots constitute the property of the Brahmanas. The sages have declared this to be an ordinance of religion. The surplus, after supporting the Brahmanas, should go to the support of other people. Nobody should take anything by doing an injury to the Brahmanas.[257] If a Brahmana, afflicted for want of support, desires to abandon a kingdom for obtaining livelihood (elsewhere), the king, O monarch, should, with affection and respect, assign unto him the means of sustenance. If he does not still abstain (from leaving the kingdom), the king should repair to an assembly of Brahmanas and say, 'Such a Brahmana is leaving the kingdom. In whom shall my people then find an authority for guiding them?'[258] If after this, he does not give up his intention of leaving, and says anything, the king should say unto him, 'Forget the past.' This, O son of Kunti, is the eternal way of royal duty.[259] The king should further say unto him, 'Indeed, O Brahmana, people say that that only should be assigned to a Brahmana which would be just sufficient for maintaining him. I, however, do not accept that opinion. On the other hand, I think that if a Brahmana seeks to leave a kingdom for the king's neglect in providing him with means of support, such means should be assigned to him, and, further, if he intends to take that step for procuring the means of luxury, he should still be requested to stay and supplied with ever those means.'[260] Agriculture, cattle-rearing, and trade, provide all men with the means of living. A knowledge of the Vedas, however, provide them with the means of obtaining heaven. They, therefore, that obstruct the study of the Vedas and the cause of Vedic practices, are to be regarded as enemies of society.[261] It is for the extermination of these that Brahman created Kshatriyas.