I was reading in Isaiah 59 recently and came across verses 15 - 17. Basically it says that God was ticked because he could find no justice in the world and no one to intervene... so he decided to step in himself! Verse 17 says that "he put on righteousness as his breastplate and the helmet of slavation on his head." And I am thinking to myself, "Wait a minute! Where have I heard that before?" I flipped over to the armor of God passage in Eph. 6 and sure enough, you know what it says. I thought to myself, "Did Paul write this with Isaiah 59 in mind? If so, it is not so much a passage on defending myself from the enemy. It's an offense passage. I put on righteousness and deliverance as well as the other armor pieces to join God in the fight against injustice. THAT's why Satan attacks me! I'm on mission wearing God's armor so that I can take out the injustices of the world. Is Eph. 6 a missions passage?
He does finish the passage with "and pray on my behalf..." and the thing he asks prayer for is boldness as he goes out for the gospel.
So the clear thought following the passage on armor, or rather the logical conclusion, is Paul's own evangelistic boldness. It might make all the preceding encouragement seem geared toward the offensive, not defensive.
So I think you might be right. I'll have to chew on that.