Commentary for Judges 5:20

War was waged from heaven. The Holy One blessed is He, as well, dispatched His hosts against them. They, too, have no desire for any payment.

They fought from heaven: That is to say, even without them, however, Sisera fell. And it was as if they fought with him from the heavens, and as if the stars swerved from their paths and from the way of their trajectories and descended and fought with Sisera. But our Rabbis, may their memory be blessed, said (Pesachim 118b) that the stars heated up the armor (such that it was too hot to touch). So they went into the Kishon Rivor to cool [it] down, but the waters of the river washed them away.

They fought from heaven: So great was the victory in which Israel defeated Sisera's army that it was as if they fought with Sisera from the heavens.

In their pathways. The upper tip of the star was in heaven, the bottom on earth. This teaches that the width of the firmament is equivalent to the distance between heaven and earth. For the star is suspended across the firmament like a sort of bolt across a door, its length measuring the same as the width of the firmament. From this passage, which attests that they waged war in their pathways, we learn that the width of the firmament is the same as the elevation of heaven from earth.³⁴“In their pathways” indicates that the star remained in its celestial path during the battle on earth. Evidently, the tip of the star remained fixed in heaven, while the remainder swung downward so that the lower edge reached the earth and destroyed Sisera’s forces. Since the star now extended from heaven to earth normally reached across the firmament, we learn that the distance between the two areas is the same.

The stars from their paths: Along the same lines as (Joel 4:11), "cause Your mighty ones to come down there, O Lord." And according to the homiletical approach (Pesachim 118b), it is that the stars heated them up, and they were wearing armor. So from the great heat, they went into the Kishon River to cool down; but the river washed them away. That is why it placed the verse of the Kishon River adjacent to the verse, "They fought from the skies." But according to the simple approach: Because the war was in the desert on the shore of the Kishon River, they went [into it] - whether to flee or whether to fight the war with Israel - but the chariots stumbled, like in Egypt, as it stated (Exodus 14:28), "He removed the wheels of their chariots." So the horsemen fell into the river, the river washed them away and they drowned. But it was not like this with Israel, but they rather marched through the river with courage, and passed through it without any incident or injury. And this is [the meaning of] that which is written (in the next verse), "march on, my soul, with courage." Meaning, with courage did my soul march through that river which washed them away. It is a sign that the heavens fought with them for my sake. And Yonatan translated (in the Targum), "march on, my soul, with courage" [as], "my soul trampled their dead warriors with power." And the explanation of the kedumim river, is that it is a river that was there from antiquity (kedem); as if it were created there from antiquity to take vengeance on the enemies of the Lord, along the lines of (Proverbs 16:4), "God did everything for His sake, etc."