Manava Dharmashastra 2.6.8

2.6.8

sa vedo viśiṣṭaḥ śabdarāśirapauruṣeyo mantrabrāhmaṇākhyo'nekaśākhābhedabhinnaḥ dharmasya mūlaṃ pramāṇaṃ parijñāne hetuḥ | kāraṇaṃ mūlam | tacca vedasmṛtyordharmapratijñāpaka tayaiva, na nirvartakatayā na ca sthitihetutayā, vṛkṣasyeva | dharmaśabdaśca prāg vyākhyātaḥ | yatpuruṣasya kartavyaṃ pratyakṣādyavagamyavilakṣaṇena svabhāvena śreyaḥsādhanam | kṛṣisevādi bhavati puruṣasya karttavyaṃ, tasya ca tatsādhanatvasvabhāvo'nvayavyatirekābhyāmavagamyate | yādṛśena vyāpāreṇa kṛṣyādervrīhyādisiddhiḥ sā'pi pratyakṣādyavagamyaiva | yāgādestu sādhanatvam yena ca rūpeṇāpūrvotpattirvyavadhānādinā tanna pratyakṣādyavagamyam | śreyaścābhilaṣitasvargagrāmādiphalaprāptiḥ sāmānyataḥ sukhaśabdavācyā | vyādhinirdhanatvāsītyanarakādiphalaprāptiḥ sāmānyato duḥkhaśabdavācyā tatparihāraśca | anye tu paramānandādirūpaṃ 'śreyaḥ' |

This ‘Veda’ is the ‘root,’ i.e., source, cause, of dharma, in the sense that it makes it known, and it does this by means chiefly of such passages in the Brāhmaṇas as contain injunctive expressions; sometimes also by means of Mantras. And the other parts of the Veda—the Arthavāda or Declamatory Passages—have their use in eulogising what is enjoined by the corresponding injunction; Mantras and names help in indicating the details of the acts prescribed.