A.T. Robertson Commentary Matthew 10:14

"And whosoever shall not receive you, nor hear your words, as ye go forth out of that house or that city, shake off the dust of your feet." — Matthew 10:14 (ASV)

Shake off the dust (εκτιναξατε τον κονιορτον). Shake out, a rather violent gesture of disfavour. The Jews had violent prejudices against the smallest particles of Gentile dust, not as a purveyor of disease of which they did not know, but because it was regarded as the putrescence of death. If the apostles were mistreated by a host or hostess, they were to be treated as if they were Gentiles (cf. Matthew 18:17; Acts 18:6). Here again we have a restriction that was for this special tour with its peculiar perils.