Vyasasmriti 3.11

3.11

sa yajñadānatapasāmakhilaṃ phalamāpnuyāt
vedebhyo'nyatra saṃtuṣṭaḥ sa vipraḥ śūdratāmiyāt
tasmādaharaharvedaṃ dvijo'dhīyīta vāgyataḥ

He obtains the entire fruit of sacrifices, gifts, and austerities. / A brahmin who takes delight elsewhere than in the Vedas falls to the status of a Śūdra; / therefore, with restrained speech, the twice-born should study the Veda every single day.