In Jeremiah 25:8 and 27:6, the Lord Almighty calls the king of Babylon, Nebuchandnezzar, His servant. His servant, the title God gives to the ruler of the most wicked nation on the planet at that time.
Read in context, we discover that God is going to use Neb's natural inclinations and activity to accomplish His purposes and further His agenda by allowing him to invade, conquer and capture the people of the nation of Israel.
All this to say that we must be careful and prayerful about what we attribute to the devil at work against us and God's Kingdom; it may just be the covert activity of God accomplishing his Kingdom purposes and plans in our lives and our world.