In regards to the revealed truth that Christ is the rock, the true foundation upon which God will build His church, Jesus said to Peter:
…. upon this rock I will build My church; and the gates of hell shall not prevail against it.
Matthew 16:18 (KJVER)
The church here is the spiritual body of Christ, not the institutional churches on Earth. The English word prevail should not be rendered overcome, as found in many lexicons and translations, but as withstand. The original meaning of the English word has drifted over the last 400 years.
The expression “gates of hell” is metaphorical for the power of Satan and his nefarious activities to destroy and kill. Thus, the meaning of this verse is that the power of Satan ultimately cannot withstand or resist the power of God in His true church.
Now, surely it has become apparent to you, as it has to me, that Satan is working overtime to destroy humans, which includes the church. He does this through human agents with the greatest amount of political and/or financial power. Such people as Adolf Hitler, Joseph Stalin, Mao Zedong, Pol Pot have been Satan’s agents on Earth. Between them they managed to kill at least 100 million people in the 20th Century.
Bible Science Forum 