I can understand a church’s desire to protect its’ people. We’ve seen far too many massacres at churches (or anywhere, for that matter). But, despite that reality, threatening more violence in reaction to violence doesn’t even remotely approach having anything to do with the teachings of the faith.
When relating the story of Jesus’ arrest in the Garden of Gethsemene, Matthew 26:52 tells us that when a disciple sought to defend Jesus from those arresting him:
…Jesus said to him, ‘Put your sword back into its place; for all who take the sword will perish by the sword.
The Here and the Hereafter 