Śatapatha Brāhmaṇa ("of a hundred paths") 1.7.2.5

1.7.2.5

atha yadeva vāsayate | tena manuṣyebhya ṛṇaṃ jāyate taddhyebhya etatkaroti yadenānvāsayate yadebhyo 'śanaṃ dadāti sa ya etāni sarvāṇi karoti sa kṛtakarmā tasya sarvamāptaṃ sarvaṃ jitaṃ

And further, inasmuch as he is bound to practise hospitality, for that reason he is born as (owing) a debt to men: hence when he harbours them, when he offers food to them, it is (in discharge of his debt) to them that he does so. Whoever does all these things, has discharged his duties: by him all is obtained, all is conquered.