Pearls before swine baby!

Now this is a command from Jesus.  What do you think it means? 

Matthew 7:6(NKJV)

6“Do not give what is holy to the dogs; nor cast your pearls before swine, lest they trample them under their feet, and turn and tear you in pieces.

I think it means don't waste your time trying to save those who have already made a decision against Jesus who just want to cause others not to believe as well. 

You know the ones I am talking about.  The ones who like to ask Biblical gotcha questions and have no interest in entering into an honest debate.  In other words, the ones who have already declared themselves to be enemies of God by rejecting Jesus.

How does that square with what Jesus said in the book of Mark?

Mark 16:15-16(NKJV)

15And He said to them, “Go into all the world and preach the gospel to every creature. 

16He who believes and is baptized will be saved; but he who does not believe will be condemned. 

Before I answer that let me remind you that contradictions don't exist.  If you think you've found one, check your premise.  (Thanks you Ayn Rand!)

Why would Jesus on the one hand say "Preach it to everyone" and on the other hand say "don't waste your time on these folks"? 

I believe the difference is that the ones He says "don't cast your pearls before swine" about are people that have already heard the message and made a decision not to follow Jesus.  In other words, as other parts of Scripture tells us, they have already declared themselves enemies of God. 

Doesn't that require me to judge them?  Not at all.  They have publicly declared that they don't believe, that they have heard the message and rejected it.  There is no judgment in that.  You are simply taking them at their word. 

Does that mean they are lost forever?  Nope, not according to Scripture as I read it.  They are free to come back and apologize to God anytime they want and He will gladly receive them.  However I believe the ball is in their court.  We shouldn't be wasting time and resources on people that have already declared their unbelief when there are people out there who haven't even heard the message yet. 

One last thing here.  Does that mean we should never engage these folks?  Not at all.  If you get the feeling that they are truly searching and looking then by all means engage with them.  But if all they want to do is steal your faith and the faith of others, don't waste your time. 

How do you tell the difference?  I believe that is where the discernment of the Holy Spirit comes into play but we'll leave that for another time.