Ambrose of Milan — as excerpted in the Catena Aurea on Luke 9:1-6

“He pronounces it to be foreign to the character of a preacher of the heavenly kingdom to run from house to house and change the rights of inviolable hospitality; but as the grace of hospitality is supposed to be offered, so also if they are not received the dust must be shaken off, and they are commanded to depart from the city; as it follows, And whosoever will not receive you when ye go out of that city, shake off the very dust from your feet for a testimony, &c.”