Mudgalapurana 3.18.25

3.18.25

brahmacārī svagotrādigṛhastheṣu mahāmune |
bhikṣāṃ caredvidhānena gurave tāṃ nivedayet ||

A student of the Veda, O great sage, should beg alms according to the rule / from householders of his own lineage and others, and should offer it to his teacher.