Albert Barnes on Matthew 10:12

And when ye come into an house, salute it. The word house, here, evidently means family, as it does in the following verse. See also Mt 12:25, Jn 4:53, "And himself believed and his whole house." The apostles were directed to salute the family, to show them the customary tokens of respect, and to treat them with civility. Religion never requires or permits its friends to outrage the common rules of social intercourse. It demands of them to exhibit to all the customary and proper tokens of respect, according to their age and station, 1Pet 2:12-25, 3:8-11, Php 4:8. For the mode of salutation, Lk 10:4, Lk 10:5.