Mark 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.
Matthew 7:6 Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.
Is preaching the Gospel to someone who doesn't want to hear it casting pearls before swine?
When preaching the gospel to the enemies. We are not to judge as to whether they will accept it or not, by trying to gauge their initial resistance.
Many muslims who resisted many witnesses of Jesus finally had moments like Soul of Tarsus (Paul) and then embraced the gospel more so than those who preached it to them.
Scripture also lends itself to the idea that we too as gentiles were once enemies....
For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. (Romans 5:10)
And you, that were sometime alienated and enemies in
your mind by wicked works, yet now hath he reconciled (Colossians 1:21)
So we are not to judge the outcome as to whether an enemy accepts it or not, rather we are obligated in our duties to proclaim the gospel regardless of the perceived outcome.
I give you another example....
Say a company employed your services to hand out advertisements of its products to every household in a suburb. When handing out these flyers do you decide whether to give a household that flyer or not, based on your perception of the outcome, as to whether they will at all buy a product. For example let us say the product is ham and you know that the house is occupied by muslims, are you in a position to decide to not give that household a flyer, no matter how obvious it may seen to you?
No, your obligation is to deliver the flyer for every household, that is what you have been employed to do. This is similar for the great commission to preach the gospel of Jesus Christ, you are obligated to preach it regardless of your perception as to the outcome of doing so.
Does your perception of what may seem obvious to you, pardon you from discharging your obligation as a witness of Jesus Christ?
Absolutely not!