Give not that which is holy unto the dogs, neither cast you your pearls before swine, lest they trample them under their feet, and turn again and rend you. Mat 7:6 Dogs and swine are unworthy of the Gospel because they reject it.     They are content to live an animalistic existence devoid of the Lord.      When a person rejects the Holy Spirit who reveals the Truth of the Gospel to them they are guilty of Blasphemy Of The Holy Ghost.

Here is how to identify a swine.   If,
   → When you mention God they flare up or
   → When you mention the Bible they flare up or
   → When you mention Jesus they flare up or
   → When you mention sin they flare up or
   → When you mention repentance they flare up
you are dealing with a swine.   

Such have rejected the Holy Spirit Of Truth Joh 16:13 .   

Stop talking to swine about Grace (pearls) and warn them of The Judgment Luk 13:3 .   

Shake their dust off your feet Mat 10:14 and go in search of a person whose heart is Good Ground Mat 13:8 .