Right before verses 14-15 of Ephesians, Paul tells us why we need the full armor of God. It is not a battle of flesh and blood, but a battle of the spiritual authorities, powers, evils, and sin that inhabits our current reality of this world. So, we do not need metal shields and camouflage barriers, but we need the tools that are equipped to us by God through the filling of the Holy Spirit to defend and march against such realities