What should I say when I hear someone give bad advice?

Question:

Hey Jeffrey,

What is the balance between expecting the world to just act like the world and to take a stand? Like I know a guy who claims to be a Christian. He was giving advice about going through divorce to someone else and he said "getting a rebound chick is the key". I'm sure he was speaking of in a fornication type of way. I was there, but wasn't really in the conversation and didn't say anything. How should I handle situations like that? 

I know we shouldn't expect the world to act like Christians, but is it wrong to not say something when I hear something I know is wrong?

Answer:

Don't think of it as right or wrong, see it as an opportunity to teach a small bit of God's Message to a lost person.

"Wait a minute! Did I hear you correctly? You're suggesting that he commit adultery because his wife left him? How does that help anyone?"

That should put the pseudo-Christian in a defensive position trying to explain why he is recommending sin. But more importantly the guy listening to him will be put on alert that he was being fed lies. It is possible that one or both will not like the questions, but at least you made them aware of the danger without coming across as "preaching" to them.