Philippians 1:12-14 "Now I want you to know, brethren, that my circumstances have turned out for the greater progress of the gospel, so that my imprisonment in the cause of Christ has become well known throughout the whole praetorian guard and to everyone else, and that most of the brethren, trusting in the Lord because of my imprisonment, have far more courage to speak the word of God without fear."

So who were the praetorian guard?  They were elite soldiers who were in charge of protecting the emperor; they also become a very important part of Roman politics.  When Paul wrote this letter he was being held by the praetorian guard.  The guards and those in Rome knew why Paul had been arrested, that he had appealed to Caesar, and that he was no normal criminal.  Because of this he would have received better treatment, but as per their practice Paul still would have been chained to at least one of the guards at all times.

Paul still would have prayed, sang, and preached while in prison and the guards had no choice but to listen, this is why Paul says that it has turned out for the greater progress of the gospel.  Not only would the guards have heard, but other Roman officials, administrators, and their families would have heard.  I'm sure curiosity got the better of some of the people who were involved in running the empire, and they wanted to hear what Paul had to say.

What was the effect of Paul's witness to the praetorian guard and the other people in Rome?  Philippians 4:22 says "All the saints greet you, especially those of Caesar's household."  Caesar's household are those people who served the empire in Rome and believed the gospel because of Paul's imprisonment.  Paul wanted the Philippians to be glad since the gospel is being furthered, even while he is in prison!

How encouraging it is to see God use the evil intentions of wicked men to accomplish good.  Joseph in Genesis 50:20 and the crucifixion in Acts 2:22-23; 4:27-28 come to mind as other examples of this.  

Do we see hardship as an opportunity to spread the gospel?  When the times get tough are we telling the gospel or trying to get out of that situation as fast as possible?