Manava Dharmashastra 6.30

6.30

ṛṣibhir brāhmaṇaiś caiva gṛhasthair eva sevitāḥ
vidyātapovivṛddhyarthaṃ śarīrasya ca śuddhaye //

(As well as those rites and texts) which have been practised and studied by the sages (Rishis), and by Brahmana householders, in order to increase their knowledge (of Brahman), and their austerity, and in order to sanctify their bodies;