For what it’s worth, I think that Catholics make much too much about the “gates of hell” promise. You take it to mean that never–not once–at any time whatsoever–will hell and hell’s ruler prevail over the Church. I think that most Protestants see this as meaning that death will not prevail because Christ has delivered us from death and hell. Also, even though our eventual victory through Christ is guaranteed, it does not mean that there shall never be setbacks. If the Catholic attitude towards this biblical passage were applied in the secular world, say the historical context of the second world war, you might phrase the promise as “the Nazis shall never prevail over the Allies”. And they didn’t…but it does not mean that the Allies never lost a battle or scrimmage…