That is a perfectly understandable reaction and one that would get affirming nods and perhaps an amen or three in most "church" settings. Respond to violence with overwhelming violence is the mantra of many churchgoing, moral Americans. Force is met with force. He brings a knife, you bring a gun. So our response is understandable in our culture but our culture, no matter how deeply ingrained it might be, should not be what defines us and forms our reactions. The question we should be asking ourselves is how we should react to this event. As hard as it is we should also think about how we should react if we found ourselves like the moviegoers, in the proverbial wrong place at the wrong time, facing a man bent on violence. It is always our best course to turn to the Scriptures in times like these and one event in particular speaks powerfully to this situation.
It is quite plausible to assume that Christians in the first few centuries saw innocent people arrested and brutally executed on a daily basis and yet they did not rise up and respond with violence. Just the opposite, often Christians were the victims of violence and did nothing to defend themselves. Jesus Himself was executed by a repressive regime and when He was arrested in the garden He rebuked Peter for trying to use violence to intervene in the defense of an innocent Man. Peter saw a violent injustice taking place and he responded in a natural way but in the wrong way. It is an event recorded in all four Gospels....
And behold, one of those who were with Jesus stretched out his hand and drew his sword and struck the servant of the high priest and cut off his ear. Then Jesus said to him, "Put your sword back into its place. For all who take the sword will perish by the sword. Do you think that I cannot appeal to my Father, and he will at once send me more than twelve legions of angels? But how then should the Scriptures be fulfilled, that it must be so?" (Matthew 26:51-54)
Now the betrayer had given them a sign, saying, "The one I will kiss is the man. Seize him and lead him away under guard." And when he came, he went up to him at once and said, "Rabbi!" And he kissed him. And they laid hands on him and seized him. But one of those who stood by drew his sword and struck the servant of the high priest and cut off his ear. (Mark 14:44-47)
While he was still speaking, there came a crowd, and the man called Judas, one of the twelve, was leading them. He drew near to Jesus to kiss him, but Jesus said to him, "Judas, would you betray the Son of Man with a kiss?" And when those who were around him saw what would follow, they said, "Lord, shall we strike with the sword?" And one of them struck the servant of the high priest and cut off his right ear. But Jesus said, "No more of this!" And he touched his ear and healed him. (Luke 22:47-51)
Then Simon Peter, having a sword, drew it and struck the high priest's servant and cut off his right ear. (The servant's name was Malchus.) So Jesus said to Peter, "Put your sword into its sheath; shall I not drink the cup that the Father has given me?" (John 18:10-11)
Jesus did not command His disciples or the legion of angels at His command to defend Him. He rebuked Peter when he attacked Malchus. He even went so far as to heal this servant of the high priest. He did everything in precisely the opposite way that we would expect.
Now a case can be made that this was a unique event and Jesus even said that He had to be taken so that His grand mission could be fulfilled. That is certainly true but His response in Gethsemane is consistent with His life, His teaching and the teaching of His disciples. We cannot overcome the world by acting like the world. We cannot defeat evil with evil. Jesus didn't conquer sin with sin, He did not overthrow evil with evil, He defeated death and hell for His sheep by love, sacrifice and submission.
As Al Mohler writes in his eloquent response to these events, we as followers of Christ must remember that evil can only be answered by a cross.
Third, we must admit that there will be no fully satisfying answer to these questions in this life. Christians know that God is sovereign, and that nothing is outside of his control. We also know that he allows evil to exist, and human beings to commit moral atrocities. We cannot allow the sovereignty of God to be denied and evil allowed its independent existence. Nor can we deny the reality of evil and the horror of its threat to be lessened. We are reminded that evil can be answered only by a cross.
The cross overcomes evil. We cannot, we must not, fall prey to the mindset of the world that sees overcoming a greater evil with a lesser evil as good and proper. We cannot live our lives in fear, arming ourselves so that we can wield justice in place of God. He has instiututed the powers of this world to deal with evil by wielding the sword but He has also called us to a different path, one that often leads to suffering and persecution and even death but has as it's reward eternal life.
When the question is raised, why does God allow evil to happen to the innocent, the Christian response must be to praise Him that He allowed, indeed ordained, the most evil event to ever occur to happen to the only truly innocent Man to ever live so that those who by nature were His enemies could be redeemed. Jesus has shown us the way by His teaching and His example. It is our calling to follow Him no matter the cost.