Have we misunderstood Ephesians 6?

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?