Skanda Purana 17.18.231

17.18.231

na vilaṃbastu karttavyaḥ śrotriye gṛhamāgate ..
abhyutthānena vacasā pādaprakṣālanena ca .. 231 ..

No delay must be made when a Vedic scholar has come to the house, / [honouring him] with rising up, with words, and with washing his feet;