Mbh 13.23.3a

"'"I have told thee what the portions are of the Rakshasas. Listen now to me as I lay down the rules for ascertaining who the Brahmana is that is deserving of gift.[213] All Brahmanas that have been outcasted (on account of the commission of heinous sins), as also Brahmanas that are idiots and out of mind, do not deserve to be invited to Sraddhas in which offerings are made to either the deities or the Pitris. That Brahmana who is afflicted with leucoderma, or he that is destitute of virility, or he that has got leprosy, or he that has got phthisis or he that is labouring under epilepsy (with delusions of the sensorium), or he that is blind, should not, O king, be invited.[214] Those Brahmanas that practise the calling of physicians, those that receive regular pay for worshipping the images of deities established by the rich, or live upon the service of the deities, those that are observant of vows from pride or other false motives, and those that sell Soma, do not deserve to be invited. Those Brahmanas that are, by profession, vocalists, or dancers or players or instrumental musicians, or reciters of sacred books, or warriors and athletes, do not, O king, deserve to be invited. Those Brahmanas who pour libations on the sacred fire for Sudras, or who are preceptors of Sudras, or who are servants of Sudra masters, do not deserve to be invited. That Brahmana who is paid for his services as preceptor, or who attends as pupil upon the lectures of some preceptor because of some allowance that is granted to him, does not deserve to be invited, for both of them are regarded as sellers of Vedic lore. That Brahmana who has been once induced to accept the gift of food in a Sraddha at the very outset, as also he who has married a Sudra wife, even if possessed of every kind of knowledge do not deserve to be invited.