To take advantage of the strength of God's might, a believer must also "put on the full armor of God, so that [he] will be able to stand firm" (Ephesians 6:11). The Greek word translated "put on" (enduo) carries the idea of permanence. The full armor of God is not something to be put on and taken off occasionally but is something to be put on permanently.
When used in a military sense, the Greek word translated "stand firm" (histemi) refers to holding a critical position while under attack. Living an obedient, Spirit-empowered life is what enables us to stand firm.