Psalm 110:2: “The LORD sends forth from Zion your mighty scepter. Rule in the midst of your enemies” (ESV).
How do you harmonize the statement that this King is to sit at the right hand of God and is to be almighty God and Lord with the fact that He is always to have many enemies and to meet with resistance of various sorts? Indeed, He is to be surrounded by enemies, as David also says later on: “Rule in the midst of Thy enemies.” How is it possible to say this of such a powerful King and the Lord of all creation? Why should He endure those who thirst to fight Him and who show themselves as enemies?
Luther, Works, 13:246.
But Christians have no armor and weapons. They must become the victims of their enemies and allow themselves to be plagued and tortured, killed and massacred. The whole issue presents itself to our senses in such a way as though this Christ were able to do nothing at all against these enemies, but had to succumb and go to pieces, together with His flock and kingdom.
This exactly is the great offense. Here is where human reason and all the wisdom of the world are offended; for “if this Christ actually were the kind of king who sits at the right hand of God, He would not rule in such a fashion.” … Well, why does God act this way? Those smart alecks and critics of God and His Word and work will neither know nor understand this but become fools with their intelligence and wisdom (Rom. 1:22), deceiving themselves. But it is disclosed to Christians that they may learn the true, divine wisdom through which He wants to be recognized. The reason is that this kingdom is to be a kingdom of faith, in which God rules in a manner strange and different from what men are able to understand or conceive. Therefore His wisdom, authority, and power are hidden to all reason. In fact, He will demonstrate them precisely by the opposite, which is called foolishness, frailty, and nothing everywhere and by all men. Thus it may be known, as St. Paul says (1 Cor. 1:25), that what appears to be foolishness in His Word and work is wiser than all the wisdom and intelligence of men, and that what appears to be weakness in Him is stronger than all the strength and power of men. Therefore in this kingdom He does not want to be a God and Savior of the strong, mighty, wise, and holy—as human reason would like to see Him, and as it also pictures Him—who do not need such a God. He wants to be a God and Savior of the weak, the unwise, the insignificant, the miserable and afflicted poor sinners who certainly need such a God and Savior. This He does in order to make them strong while they are weak, righteous and joyful while they are convinced and frightened by sin, alive and blessed while they suffer and die; as He says (2 Cor. 12:9): “My power is made perfect in weakness.” He does this, and must do it, especially to thwart and vex both His enemies, the devil and the world, that they may experience in the end what His wisdom, authority, and power—which they judge to be impotent and V 13, p 254 nothing—really are and can do.
Luther, Works, 13:252-54.
To put it succinctly, the enemies are defeated and subdued by the divine power and miracle alone, without the resistance of the Christians or any physical power at all. “For I will do it Myself,” He means to say here, “and in such a way that Christians will need neither armor nor sword nor weapons. Let them remain quiet and do nothing but attend to their duty of preaching about this Lord and His kingdom, and tell how God has ordained Him King at the right hand of God and Lord of all creation. Let Me handle those who despise and reject this or oppose themselves to it and persecute the Christians for it. I will take care of revenge. I will put a damper on their power and might and will overthrow them. I have more than enough power and might to lift them out of their thrones and cast them under the feet of this Christ. Sufficient for Christians—and let this be their comfort—is My promise that their enemies shall not accomplish their designs; for I have ordained it and spoken the judgment that they shall and must become the footstool of this Christ, whether they like it or not.”
Luther, Works, 13:255-56.