I snarked on Facebook earlier this week that everybody loves to talk about the shield of faith and the sword of the spirit, but we don't talk about the sandals of the gospel of peace. That's a shame, because it's the only item mentioned in that passage from Ephesians that has anything to do with active interactions with other people.
The entire passage is defensive in context--the breastplate, shield, helmet, etc. are protections meant, not to aid in conquering, but to help the Christian to "withstand" and "stand firm" against the evil one. But we are instructed to put on our feet "whatever will make you ready to proclaim the gospel of peace."
Truth. Righteousness. Faith. Salvation. The Spirit and the Word of God. And the shoes of whatever will make you ready to proclaim the gospel of peace.
Whatever makes you ready.
What will make us ready to proclaim the gospel of peace? We're not told, and perhaps that's because evangelization is always, as Cardinal Newman believed, a matter of heart speaking to heart. It is personal, and it requires you to be present to the person and the moment in a way that can't be scripted.
So how do we prepare for this improvisation? We're told elsewhere: "in your hearts honor Christ the Lord as holy, always being prepared to make a defense to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect, having a good conscience" (1 Peter 3:15). And the passage about the armour of God in Ephesians ends with the reminder to "Pray in the Spirit at all times in every prayer and supplication. To that end keep alert and always persevere in supplication for all the saints."
The world has never not been at war with itself, which means that martial imagery is not going to go away. It's rich ground for metaphor. But the metaphor of spiritual warfare stands the image of the battle between us and them on its head by placing both side of the battle within the self.
I can't storm the enemy's front; I am the front. To fight the battle against evil within, I need truth, faith, the Word. All of these things so that I can stand firm. And when I walk among other people, I need to walk in whatever will make me ready to proclaim the gospel of peace.
Gradually it was disclosed to me that the line separating good and evil passes not through states, nor between classes, nor between political parties either - but right through every human heart - and through all human hearts. This line shifts. Inside us it oscillates with the years. And even within the hearts overwhelmed with evil, one small bridgehead of good is retained. And even in the best of all hearts, there remains…an un-uprooted small corner of evil. Since then I have come to understand the truth of all the religions on the world. They struggle with the evil inside a human being (inside every human being).