In the cities and towns, the disciples were to inquire who was worthy.  Certainly this does not mean finding those who were worthy of receiving salvation, but rather it directs the disciples to seek out those who were eager to receive the good news of the kingdom.  It is these humble seekers whom God counts worthy to receive His grace; not because of goodness in them, but because He has made them humbly willing to receive His word.  There the disciples were to abide, and if they were well received, and their message believed, their peace would remain upon that particular house.  They were sent forth as heralds of the Gospel of Christ, and the message they carried is one of life or death.  Therefore, they were to symbolically shake off the dust of their feet against those towns which would not receive them (as we find Paul doing against the Jews in Antioch-Pisidia).  This was meant as an indication that, since they had shaken off the Gospel message, God would shake them off.  Christ says of them these disturbing words, “It shall be more tolerable for the land of Sodom and Gomorrha in the day of judgment, than for that city.”  Truly, to reject the Gospel message is a most serious matter, and invites the fiercest thunderbolts of divine judgment!