Isa 52:15 So shall he sprinkle many nations; the kings shall shut their mouths at him: for that which had not been told them shall they see; and that which they had not heard shall they consider.
Isa 53:1 Who hath believed our report? and to whom is the arm of the LORD revealed?
Everyone should be given the chance to hear the gospel message.
Mat 24:14 And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.
Do not continue to give the gospel to someone who rejects it, move on where another is seeking what you have to share. Paul proved his apostolic calling. He went to areas completely unaware of his gospel message with boldness in the Holy Ghost. It is not uncommon today to meet people who have never been to church and have little understanding of who Jesus is.
Joh 14:6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Lord save the lost from their sins, in Jesus name amen.