For every trampling boot of battle and every garment rolled in blood will be burned as fuel for the fire.
5. For every battle. Here commentators are nearly agreed that Isaiah intended to contrast the victory which God was about to give to his people with other victories. Others conquer by making a great slaughter of the enemies, but here the Lord will conquer by his own hand alone. He expresses more fully what he had said, As in the day of Midian.
The first words of this chapter plainly refer to the close of the foregoing chapter, where every thing looked black and melancholy: Behold, trouble, and darkness, and dimness - very bad, yet not so bad but that to the upright there shall arise light in the darkness (Psa 112:4) and at evening time it shall be light, Zac 14:7.
Commenting on Isaiah 9:1-7
For every battle of the warrior is with confused noise,.... With the sound of the trumpet and as now with beating of drums, and the huzzas and shoutings of the soldiers, the stamping and neighing of horses, the rushing of chariots, and rumbling of wheels, and the clashing of swords, spears, and shields, and these sometimes striking one against another (k): and garments rolled in...