If the Devil no longer has power and authority over us, why does the Bible command us to put on the full armor of God?
The Lord's decisive defeat of the Devil through the cross does not mean we are no longer involved in spiritual battles and fierce struggles. The Lord Jesus has already won the war, but we are still engaged in spiritual battles against the powers of darkness (Eph. 6:12). Sometimes these battles are fierce. But it is important to note what the text says. It says, “put on the full armor of God, so that you can take your stand against the devil's schemes” (Eph. 6:11). The text does not say stand firm against the power of the Devil, but stand firm against the schemes of the Devil. His power was broken at the cross, but we do have to be prepared to stand against his schemes. These schemes are his diabolical methods, his cunning strategies that he uses to catch us off guard, to tempt us, and to deceive us. Armed, however, with the power and armor of God, we are enabled to stand against the cunning methods of the Devil.