Through the years, there have been those who have set themselves against the church and have tried to destroy it. The Roman emperor, Diocletian, set up a stone pillar on which these words were inscribed: "For having exterminated the name Christian from the earth." I wonder how he would feel if he could see the monument today. It didn't work.
There have been those who have tried to stop the work of God. Communist countries, for example, have tried. One Roman leader made a coffin to symbolize his intention, in his words, to "bury the Galilean" by killing His followers. But he soon learned that he could not put Jesus in that coffin. Finally, he ended up believing in the One that he tried to destroy. Nothing and no one has ever been able to stop the church, because Jesus established it, and He said, "The gates of Hell shall not prevail against it."
Now, the devil will not cooperate with our attempt to get the gospel out. He will oppose it with everything that he has. "The gates of Hell" refers to the forces of the devil, and when Jesus says the gates of Hell shall not prevail against the church, He is not saying that these forces will not try to attack us. Rather, what He is saying, primarily, is that as we move forward as soldiers in His army, the devil's opposition will not prevail. The truth of the matter is that he will lose in the end.
We may lose a battle here and there. But clearly, we will win the war in the end.