For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places.
Ephesians 6:12 ESV

In his book, Let the Nations Be Glad, John Piper dedicates the second chapter to discussing the role of prayer in missions. He opens up the chapter like this:

Life is war. That’s not all it is. But it always that. Our weakness in prayer is owing largely to our neglect of this truth. Prayer is primarily a wartime walkie-talkie for the mission of the church as it advances against the powers of darkness and unbelief. It is not surprising that prayer malfunctions when we try to make it a domestic intercom to call upstairs for more comforts in the den. God has given us prayer as a wartime walkie-talkie so that we can call headquarters for everything we need as the kingdom of Christ advances in the world. Prayer gives us the significance of frontline forces and gives God the glory of a limitless Provider. The one who gives the power gets the glory. Thus, prayer safeguards the supremacy of God in missions while linking us with endless grace for every need.

Verses 10-17 give us the necessary context for verse 18, so it is important that we spend at least a moment discussing them. In a nutshell, Ephesians is primarily about how individual Christians come together to glorify God as the Church, and throughout the letter, we find how the Church ought to pray, how we ought to worship, and various other things. Within these verses, Paul teaches us how to fight, how to wage spiritual warfare.

In discussing spiritual warfare, we must be careful to avoid two equally damaging extremes.

On one end, we have (typically) charismatic Christians who can often make spiritual warfare a de facto primary doctrine. They can become obsessed with defeating Satan in Jesus’ name, and often even speak to Satan directly in order to rebuke him.

But you also have less charismatic denominations that err to the opposite extreme of rarely, if ever, mentioning spiritual warfare. We talk about of sin and struggles, but we don’t talk about Satan. We let God deal with him. Both extremes are harmful. Neglecting and making it the centerpiece of our walk with Christ are equally damaging practices.

This passage calls us, as followers of Christ, to war. We cannot neglect this truth. We are in the midst of a battle with stakes that are higher than any earthly war ever waged. Although all war is serious and devastating, World War II stands apart from others. The Nazis, armed with heinous ideals and brutal death camps, are difficult to rival when imagining the epitome of evil in the world. Thus, in many ways, World War II was a fight for the world’s soul. In that battle against evil, millions of soldiers lost limbs and millions more lost their lives.

Yet as grisly as that war’s spectacle was, it pales in comparison to the stakes of this war. In this war, people lose not merely their lives but their eternity. Victims of this war will spend an eternity cast out of God’s presence and under the outpouring of His wrath.

Christ came to bring His kingdom to earth. Historically, kingdoms often find themselves warring against other kingdoms, and Jesus’ kingdom is no different. All of creation falls under the realm of one of two kingdoms: the kingdom of God or the kingdom of darkness. There is no neutral ground. We are either soldiers for God or for the enemy.

This means that making disciples is spiritual warfare. If we are each a member of either the kingdom of God or the kingdom of darkness, then expanding God’s kingdom means bringing people out of darkness into light. Making disciples, the mission of each Christian and church, is also God’s strategy for waging war.

It is upon this thought that Paul launches into the subject of prayer. The full armor of God is necessary, but prayer is the force that makes the armor usable.

Without prayer, faith is not our shield.

Without prayer, the readiness of the gospel does not gird our feet like shoes.

Without prayer, we cannot properly wield the Word of God as a sword.

If we strip prayer out of its warfare context, we risk turning it into something that is biblically unrecognizable.