Mahabharata 13.72.32

13.72.32

brāhmaṇasya phalaṃ hīdaṃ kṣatriye'bhihitaṃ śṛṇu |
pañcavārṣikametattu kṣatriyasya phalaṃ smṛtam |
tato'rdhena tu vaiśyasya śūdro vaiśyārdhataḥ smṛtaḥ || 32 ||

Devoted to truth, possessed of a tranquil soul, free from cupidity, always truthful in speech, and behaving with reverence towards kine with the steadiness of a vow, the man, who, for a whole year before himself taking any food, regularly presents some food to kine, wins the merit, by such an act, of the gift of a thousand kine. That man, who takes only one meal a day and who gives away the entire quantity of his other meal unto kine.--verily, that man, who thus reverences kine with the steadiness of a vow and shows such compassion towards them,--enjoys for ten years' unlimited felicity. That man, who confines himself to only one meal a day and 'with the other meal saved for some time purchases a cow and makes a gift of it (unto a Brahmana), earns, through that gift, O thou of a hundred sacrifices, the eternal merit that attaches to the gift of as many kine as there are hairs on the body of that single cow so given away. These are declarations in respect of the merit that Brahmanas acquire by making gifts of kine. Listen now to the merits that Kshatriyas may win. It has been said that a Kshatriya, by purchasing a cow in this manner and making a gift of it unto a Brahmana, acquires great felicity for five years. A Vaisya, by such conduct, acquires only half the merit of a Kshatriya, and a Sudra, by such conduct, earns half the merit that a Vaisya does.