Acts 19 verses 21-41, can be broken down into three sections: First, Paul's spirited plan of where he wants to go; second, the pagan mostly peaceful protest; and third, the politicians wise words to dispan the protest.

Paul put forth his spirited plan to travel to new places including Rome with the goal of spreading the good news.  Gods work through Paul and the other followers showed the growth of Christianity through Asia,  Paul now wanted to reach Rome to spread the news about God.  

Prior to leaving Ephesus, the Tradesman stirred up by Demetrius who made images of the Artemis and other Gods in Silver led a protest against Paul and the Christians, because they were hurting their businesses of selling these Idols. 

The City Clerk finally quieted down the crowd and pointed out that they had no reason to go after Paul and the other Christian, but if they had any true claim against them, then settle it in the courts and not with mob brutality which is against the law. 

Several things shown in this story points to how the Gospel works.  The Gospel can be bad for business if their businesit is working against the Gospel and Gods will.  The Gospel may also be bad for your physical health in that when spreading the Good News, you will be persecuted.  Satan is always against the Gospel and will try to throw roadblocks in your desire to practice and spead the news.  The Gospel cannot be stopped. You must put the Gospel/God first above all else.  Christians are to avoid mob mentality and cannot be violent.  Christians need to be good examples, like Paul and follow the Gospel.  Christian should also try to resolve issues calmly by putting their trust in the True God. 

In Summary, Love the Lord God with all your heart, soul and mind and put him above all esle and strive to follow his ways and trust in him for everything.