Luke 9:5

Jewish travelers often shook the dust off their feet when they returned from a journey in Gentile territory to reject symbolically the Gentiles’ uncleanness. [Note: Marshall, The Gospel . . ., p. 354.] When the Twelve did this, it represented rejection of the unbelievers who had not received their message and them (cf. Acts 13:51; Acts 18:6). It symbolically stated that Israelites who rejected the disciples’ preaching were no better than unbelieving Gentiles. Evidently Jesus meant this as a sign of individual, but primarily citywide, rejection (cf. Matthew 10:14-15).