Then he called his twelve disciples together, and gave them power and authority over all demons, and to cure diseases.
All Commentaries on Luke 9:1 Go To Luke 9
Bede
AD 735
The dust is shaken off from the Apostles' feet as a testimony of their labors, that they entered into a city, and the apostolicalpreaching had reached to the inhabitants thereof. Or the dust is shaken off when they receive nothing (not even of the necessaries of life) from those who despised the Gospel.
But if any by treacherous negligence, or even from zeal, despise the word of God, their communion must be shunned, the dust of the feet must be shaken off, lest by their vain deeds which are to be compared to the dust, the footstep of a chaste mind be defiled.