which He exerted when raising Christ from the dead and seating Him at His right side in the heavenly realms [i.e., heaven itself].

You practiced such things when you lived according to the evil ways of this world, and according to the ruler of the [spiritual] powers of the air. [Note: This refers to Satan, whose influence permeates life around us]. He is the [evil] spirit who is now at work in people who are disobedient [to God].

So, when you read this you will be able to understand my insight into the secret plan of Christ,

I urge you, therefore, as a prisoner of the Lord, to live in a way that measures up to [the standard required by] God when He called you.

There is [only] one body [i.e., church] and one Holy Spirit, just as God also gave you one hope when He called you [See Titus 3:7].

Therefore, it says [Psa. 68:18], "When He ascended on high [i.e., to heaven], He led a procession of captured prisoners [behind Him] [Note: This originally referred to God leading His people in triumph over Israel's enemies, but here is applied to Christ], and gave gifts to [various] people."

for you people were once darkness [i.e., when living in sin], but now you are light in [fellowship with] the Lord. [So], live like people who belong to light [i.e., who live godly lives],

But when all [such] things are exposed by the light [i.e., the truth], they become [clearly] visible [i.e., their true nature is revealed], for everything so revealed becomes illuminated. [Note: Possibly this means "it is light that clearly reveals everything"].

Do not serve them only when you are being watched, just to gain their approval, but as slaves of Christ, doing what God wants from your heart.

Therefore, put on the full armor of God, so that you can withstand [the devil, See verse 11] when the evil day comes. And, after you have done everything you can, still remain standing firm [in the faith].