This text is usually interpreted as if the gates of hell were some kind of offensive weapon being used against the church. However, gates are not offensive weapons; rather they are used as a defense against an attacking force or to prevent prisoners from escaping. Is Jesus saying that the church is being attacked or that the church is storming the gates of hell? What does it mean to "not prevail"? What are the gates of hell, anyway? For that matter, what is hell? There are all sorts of ideas of what hell is. Some say it is the everburning place of the damned where the wicked, along with Satan and his angels are tortured forever. Others say it is the final conflagration in which the wicked are destroyed and the earth is melted down and then recreated. Some say that it refers to death and the grave. This is because the word "hell" is used with different meanings in different places.
In this particular text, Matthew 16:18,19, there is no mention of hell fire, but as a place with gates. Secondly. this place is described as a prison house, and the gates pictured here are guarding a prisonhouse. We have an example in the Berlin wall which was designed solely to keep people in rather than keeping people out. The Brandenberg gate was guarded 24 hours a day to prevent the escape of people fleeing the communist USSR. Many people lost their lives in an attempt to escape. However, some people did escape, and for those the gates did not prevail. The gates failed to prevent their escape. Similarly, the gates of hell shall not prevent the escape of some of those who are imprisoned.
Christ's triumph over death and the grave is the central theme of Christianity. It was not possible for the chains of death to hold Christ captive, nor will it be possible for any of His followers to be so held. Satan guards the gates of his prison, but Christ entered Satan's stronghold, bound the adversary, and has set the prisoners free. He took "captivity captive."
"I am he that liveth, and was dead; and behold, I am alive for evermore, Amen; and have the keys of hell and of death." Rev. 1:18, KJV.
Conclusion: The gates of Hell, or the grave, could not hold Christ, and it cannot prevent the escape of Satan's prisoners for Christ has bound Satan and wrested the keys from his hands and unlocked the gates. Thus their escape cannot be prevented by "the gates of hell"
