We do not have the power to defeat Satan and his minion of demons without the armor and intervention of God. Paul evidently had become acquainted with Roman soldiers to derive this metaphor. The helmet, constructed of bronze and iron, protected the head and was essential to survival, protecting the soldier against battleaxes. Likewise, our spiritual helmet, symbolizing the salvation coming from Christ, protecting our minds from disorientation and confusion, keeps us from disinformation and subtle lies (fiery darts) from Satan the Devil, attempting to separate us from God. To survive our horrendous spiritual battles, we need to be putting on Christ daily through meditation and studying His word.