The Great Epic of the Bhārata dynasty 3.177.18

3.177.18

sarpa uvāca |
cāturvarṇyaṃ pramāṇaṃ ca satyaṃ ca brahma caiva ha |
śūdreṣvapi ca satyaṃ ca dānamakrodha eva ca |
ānṛśaṃsyamahiṃsā ca ghṛṇā caiva yudhiṣṭhira || 18 ||

"The serpent said, 'O Yudhishthira, truth, charity, forgiveness, benevolence, benignity, kindness and the Veda which worketh the benefit of the four orders, which is the authority in matters of religion and which is true, are seen even in the Sudra. As regards the object to be known and which thou allegest is without both happiness and misery, I do not see any such that is devoid of these.'