To shake the dust off our feet.

"If any household or town refuses to welcome you or listen to your message, shake the dust of off you feet as you leave." Matthew 10:14
If you have read the Gospels then you no doubt have heard this and even if you haven't you have no doubt heard some one say some version of this before. It is one of those scriptures that gets taken out of context alot.Most people take it has meaning to completely abandon the people or places who do not welcome your ways. This cannot be. Jesus instructs us to love every one. He teaches us through His actions that He has a distaste for sin but a love for everyone. We see this in Judas. He loved Judas and allowed Jesus to be with Him through out His ministry. If he meant to leave behind all those who did accept what we believed He would have never chosen Judas.
Judas remained a thief. The apostles knew this and so did Jesus. Jesus knew He would betray Him. He was self centered and only wanted what was good for Him. Yet Jesus let Him stay with Him and all the other apostles. He taught the apostles to shake the dust off of their feet. That includes the dust of Judas.
You see when He said dust he was using another parable. When people in those times would go into a town where they worshiped a pagan god they would shake off their feet as a symbolic refrence to them leaving the evil ways behind in the city. Do not worship their false gods, do not commit the sins they do. This is what Jesus was saying. If we go to a friends house and lets say they participate in drinking, drugs, or sex with out being married. We can still be their friends but we don't have to let their sins leave their house with us. We can leave that persons house and leave the sins them. Don't go do what they are doing. Leave the beer there, don't ask his girl's friend to come with you.
We do (and we have no choice in all cases) live in a sinful world and are close to sinful people. Just because they sin doesn't mean we have to do the same. Just because you boss cusses doesn't mean you have cuss. Judas didn't influence the others to betray Jesus or to steal because they knew that one persons sin should not be their own. Live your life holy and pure. You will fall short but don't live in sin. You will have to talk to friends and family who live a lifestyle you don't approve of. That in no way means you have to live that lifestyle. Just has the scripture of Matthew 10:14 does not give you the right to give up on people.