You are in a battle

Romans 13:12 “The night is far gone; the day is at hand. So then let us cast off the works of darkness and put on the armor of light.”

1 Thessalonians 5:8 “But since we belong to the day, let us be sober, having put on the breastplate of faith and love, and for a helmet the hope of salvation.”

Panoplia of God - the full set of armor a Roman foot soldier would wear into battle.

2 Corinthians 6:7 “by truthful speech, and the power of God; with the weapons of righteousness for the right hand and for the left;”

2 Corinthians 10:3–6 “For though we walk in the flesh, we are not waging war according to the flesh. For the weapons of our warfare are not of the flesh but have divine power to destroy strongholds. We destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ, being ready to punish every disobedience, when your obedience is complete.”

1 Timothy 1:18 “This charge I entrust to you, Timothy, my child, in accordance with the prophecies previously made about you, that by them you may wage the good warfare,”

2 Timothy 2:3–4 “Share in suffering as a good soldier of Christ Jesus. No soldier gets entangled in civilian pursuits, since his aim is to please the one who enlisted him.”

It is the armor of God because it is the armor that God supplies.

This armor is so you can stand, not secure the victory (withstand, to stand, stand).

You are to stand firm against the onslaught of the Devil.

The Devil is actively planning and strategizing how to make you retreat or fall.

Wrestle - in all likely used to indicate the closeness of the fight. No one can do it for you and its not done at a distance - close-quarter, hand-to-hand combat.