This last piece of the armor of God is critical as it is calling on the power of the Almighty God without which we can’t win.
Imagine you’re in the heat of the battle, supplies are running out, ammo is depleted, the enemy is advancing, and the radio is out. Can’t call for additional support, can’t call for supplies. No ammo—not help—you are at the mercy of the approaching enemy—no way to call for help. In spiritual warfare it is also true. Without communication with the Father you are spiritually disabled—fear overpowers your mind—hopelessness your thoughts. Without comprehensive prayer we become as before we were saved: —“without Christ, strangers from the covenants of promise, having no hope and without God in the world” (v.2:12). Not being able to communicate with our Father leaves us alone—without the hope, without wisdom and the knowledge that He is always there to help and guide us.
Remember the exhortation is to put on the whole armor of God. Thus, even after we have girded our waist with truth, after putting on the breastplate of righteousness…Even after we shod our feet with the preparation of the gospel of peace; after taking the shield of faith, the helmet of salvation, and the sword of the Spirit…Leaving out prayer we become soldiers in a spiritual battle and should expect only one conclusion—the loss of the soul. Prayer is the means of receiving the lifeline needed to survive the attack of the devil. A life that is dependent on God in prayer is essential for standing in the faith. The sons of Korah wrote, “God is our refuge and strength, a very present help in trouble” (Psa. 46:1).
Therefore Paul says, “praying always with all prayer and supplication in the Spirit, being watchful to this end with all perseverance and supplication for all the saints—” (Ephesians 6:18).