Was the Roman soldier's armor designed for retreat or only for forward attack?

Les explains that Paul frequently used the Roman army or soldier as an illustration. The armor and equipment of the Roman soldier, he notes, were designed for only one direction: forward. There was never room for retreat and never a rearguard action. Everything Paul denotes in the passage was for a frontal attack. Les contrasts this with liberals who criticized the hymn "Onward, Christian Soldiers" as too militant or confrontational, suggesting that perhaps that mindset has affected the church. He says believers must be confrontational up to a point—not obnoxious—but able to stand against the powers in high places.