And if that house is worthy, your peace will come upon it, but if it is not worthy, your peace will return to you.
In this passage Jesus urges the disciples to discern the people they visit during their preaching journeys. If a house is worthy (that is, if the residents receive them and their message), the greeting of peace and blessing should rest on them. But if the house or the people do not receive them, that greeting should return back, meaning they should continue on their way as they were going. This shows that the word of God is offered to all, but not forced on anyone.