The painful and debilitating disease of 'trench foot' has caused more soldiers to leave the front line than enemy fire.  Napoleon's army suffered severely in the retreat from Moscow.  In World War 1 Allied forces were decimated around the Somme by feet that became so diseased that they were unable to advance. Soldiers were instructed to dry their feet and change socks twice a day, coating their feet with whale grease to stop the skin going soggy and being infected: if gangrene set in, amputation was the only solution.  Roman soldiers also knew that footcare was critical.  Their caligae (sandals) were renowned for their hard wearing, robust design with hob nailed soles and ankle support: the lattice of leather also allowed the feet to be ventilated to prevent disease.  As the Roman infantry was required to march 25 miles a day during campaigns, carrying around 35kg of kit, footwear had the highest priority.  Gaius Julius Caesar had the nickname 'Caligae' as a boy growing up with his father in military camps.  He was the 'ready-to-go anywhere' soldier.

This verse points to the 'always-ready' feet.  The gospel, which Christians believe, announces Jesus' defeat of evil and the way for prodigals to return to Father God (Isaiah 52:7).  Those believers who love and proclaim the gospel are totally secure: whatever the evil attack, there is no reason to slip over or to run away.  The gospel enables us to stand firm because the 'sandals' grip well with the studs of saving grace.  Paul was not ashamed of the gospel (Romans 1:16); he would stand on its truth and stand by its power.  However, the gospel is not just about inducing a fresh confidence; if it is true - then it must be proclaimed.  Alas, many Christians are inclined to shrivel up at the first sign of difficulty or opposition; they are preoccupied with self-preservation ... and, like the weaklings of the herd, they are soon picked off by the demonic hyaena.  But those Christians who are ready and eager to take enemy territory, after the barrage has finished for the moment - they are the most likely ones to stand under attack.

Any army that retreats to the safety of home territory cannot win the war. Any business that will not go out to the market will be overtaken by the market. Yet, in the West, thousands of churches have retreated to their bunkers - ignoring the millions held hostage by Satan, as they enjoy peace with God.  But the gospel is not intended to be a closed-circuit message system to reinforce the well-being of Christians.  It is meant for the loudspeaker and leaflet drop over the enemy lines saying that Jesus is ready to rescue.

In once-Christian Britain, declining UK church attendance indicates that more people are dying than are being converted. The reason for that is that Christians are not ready to bring the gospel to so many who the devil is terrorising. Small wonder that Paul says that Christians need gospel boots and not religious slippers!  If the enemy can get us to take off our gospel boots for even a day, he can knock us off our feet more easily, and ensure that his hostages remain unsafe under his authority.  And there are lots of hostages in your workplace.  So ... strap on those caligae, and be ready to advance with Jesus' peace plan when the latest attack has died down!