"Take nothing for the journey except a staff - no bread, no bag, no money in your belts. Wear sandals but not an extra tunic.
Whenever you enter a house, stay there until you leave that town. And if any place will not welcome you or listen to you, shake the dust off your feet when you leave, as a testimony against them."
Mark 6:8-11
Don't Know What to Say to Them?
1) Jesus asked His disciples to rely totally and completely on His providence when we go forth to do His work. He will supply all our needs, supernaturally (manna from the sky) or through other people. He will give us the very words to say to our friends.
Disappointed at Their Responses?
2) Our responsibility to reach out to a certain someone is AFTER we've shared and if they do not welcome us or listen to us, then we can 'shake the dust off your feet' - i.e. we have done our part. Thus, we must SHARE the gospel then we are released from our responsibility.
Let's do our part, SHARE and watch God work out the rest.