John Calvin Commentary Ephesians 6:11

"Put on the whole armor of God, that ye may be able to stand against the wiles of the devil." — Ephesians 6:11 (ASV)

Put on the whole armor. God has equipped us with various defensive weapons, provided we do not slothfully refuse what is offered. But almost all of us are guilty of carelessness and hesitation in using the grace offered to us; just as a soldier, about to meet the enemy, might take his helmet and neglect his shield.

To correct this complacency, or, we should rather say, this sloth, Paul draws an analogy from warfare and instructs us to put on the whole armor of God. We should be prepared on all sides, so that we lack nothing. The Lord offers us weapons to repel every kind of attack.

It remains for us to put them to use and not leave them hanging on the wall. To sharpen our vigilance, he reminds us that we must not only engage in open warfare but that we have a crafty and insidious foe to encounter, who frequently lies in ambush; for such is the meaning of the apostle’s phrase, THE WILES (τὰς μεθοδείας) of the devil.