Śatapatha Brāhmaṇa ("of a hundred paths") 2.3.1.8

2.3.1.8

atha yaḥ purādityasyāstamayāt | āhavanīyamuddharati yathā śreyasyāgamiṣyatyāvasathenopakLptenopāsītaivaṃ tatsa yasyoddhṛtamāgacanti tasyāhavanīyam praviśanti tasyāhavanīye niviśante

And another reason why he takes out the Âhavanîya before the setting of the sun, is this. In like manner as, when one's better comes to visit one, he would honour him by trimming his house, so here: for whosesoever (offering) they approach, after the fire has been taken out, his Âhavanîya (house) they enter, in his Âhavanîya they repose.