The Law Code of Yājñavalkya 3.1.1

3.1.1

gṛhasthāśramiṇāṃ nityanaimittakā dharmā uktāḥ | abhiṣekādiguṇayuktasya gṛhasthaviśeṣasya guṇadharmāś ca pradarśitāḥ | adhunā tadadhikārasaṃkocahetubhūtāśaucapratipādanamukhena teṣām apavādaḥ pratipādyate | āśaucaśabdena ca kālasnānādyapanodyaḥ piṇḍodakadānādividher adhyayanādiparyudāsasya ca nimittabhūtaḥ puruṣagataḥ kaścanātiśayaḥ kathyate, na punaḥ karmānadhikāramātram, aśuddhā bāndhavāḥ sarve (MDh 5.58) ityādāv aśuddhatvābhidhānāt, aśuddhaśabdasya ca vṛddhavyavahāre 'nāhitāgnidīkṣitādāv anadhikārimātre prayogābhāvāt, vṛdddhavyavahāravyutpattinibandhanatvāc ca śabdārthāvagḥateḥ | kiṃ ca yady āśaucināṃ dānādiniṣedhadarśanāt tadayogyatvam aśaucaśabdābhidheyaṃ kalpyate, tarhi udakadānādividhidarśanāt tadyogyatvam apy āśaucaśabdābhidheyaṃ syāt | tatrānekārthakalpanādoṣaprasaṅgaṃ ity upekṣaṇīyo 'yaṃ pakṣaḥ ||

The regular and occasional duties of householders have been stated. And the duties based on specific qualification of a particular householder endowed with qualifications such as royal consecration have been shown. Now, an exception to these is set forth by means of establishing ritual impurity, which serves as the cause for the restriction of their qualification. And by the word 'impurity' (āśauca) is meant a certain inner state belonging to a person, which is to be removed by time, bathing, and the like, and which serves as the cause for the injunction of offering water and rice balls and for the exclusion from recitation and the like—not merely the lack of qualification for ritual acts. For lack of purity is stated in such passages as "All relatives are impure" (MDh 5.58), and in the usage of learned elders, the word 'impure' is not applied to everyone merely disqualified, such as one who has not established the sacred fires or an initiated sacrificer; and the understanding of word-meaning is grounded in the usage of learned elders. Furthermore, if, seeing the prohibition of giving gifts and so forth for impure persons, their unfitness for that were assumed to be the referent of the word 'impurity', then, seeing the injunction of offering water and so forth, their fitness for that would also have to be the referent of the word 'impurity'. That would involve the flaw of positing multiple meanings; therefore, this view must be rejected.