You shall break them with a rod of iron; You shalt dash them in pieces like a potters vessel.
Here the vain dreams of the flesh are to be removed, and no one is to imagine that the kingdom of Christ is either founded on or preserved by iron or arms; because it is written that he delighted not in chariots, nor in horses, nor in the legs of a man. The apostle says: "The weapons of our warfare are not carnal." The Turks, whom at this day we never seek to conquer by any other means than the sword, we ought to conquer by increasing the number of Christians among them. Why do we not attack with the sword also the wicked among ourselves? But God forbid. The kingdom of Christ consists in righteousness, truth and peace. By these it was obtained and by them it will be preserved. Hence, when he said above that he was appointed king, he recommended no other office whatever than that of the Word, saying, "I will declare the decree of God," not, I will ride fine horses, I will lay waste cities, I will seek the treasures of the world; but I will do this one thing — declare those things which God has commanded, that is, that Christ is God and man, which Paul calls the gospel, saying, "Separated unto the gospel of God, which he had promised before, concerning his Son Jesus Christ." You see that this whole verse is an allegory which really takes place in fact and life. As the word "Christ" is the word of salvation and peace, not in the flesh, but in the spirit, it follows of necessity that it subdues and drives out the safety, peace and easy life of the flesh. Where it does this, it appears unto the flesh harder and more unfeeling than iron itself.
Wherever the carnal man is touched by the Word of God, one thing is felt, another is killed, namely, "The Lord kills and makes alive." Though God is the God of life and salvation and these are his proper works, yet, in order to accomplish these, he kills and destroys, that he may come unto his proper work. He kills our will, that he may establish his own in us. He mortifies the flesh and its desires, that he may implant the Spirit and his desires; and thus "the man of God is made perfect, thoroughly furnished unto all good works."