1 Thes. 2:14-20 (ESV)
For you, brothers, became imitators of the churches of God in Christ Jesus that are in Judea. For you suffered the same things from your own countrymen as they did from the Jews,  who killed both the Lord Jesus and the prophets, and drove us out, and displease God and oppose all mankind
 by hindering us from speaking to the Gentiles that they might be saved—so as always to fill up the measure of their sins. But God's wrath has come upon them at last!
 But since we were torn away from you, brothers, for a short time, in person not in heart, we endeavored the more eagerly and with great desire to see you face to face,  because we wanted to come to you—I, Paul, again and again—but Satan hindered us.  For what is our hope or joy or crown of boasting before our Lord Jesus at his coming? Is it not you?  For you are our glory and joy.
Who drove us out, and displease God and oppose all mankind by hindering us from speaking to the Gentiles that they might be saved. If one could be saved by the law, then speaking would not be of any necessity. But because the Gospel is Good News that needs to be heard in order to be believed speaking is of great importance. Paul here is not so much concerned that they hate him, or despise him. He is concerned one that they displease God. They probably don’t see it the same way. People often do reprehensible things in the name of God thinking that they are pleasing him. And 2 that they oppose all mankind. They oppose them because they won’t let them hear this Good News that Jesus Christ has died for their sins, and come back from the dead as evidence that we will also. If they can’t hear they can’t be saved.