They fought from heaven - The angels of God came to the assistance of Israel: and the stars in their orbits fought against Sisera; probably some thunder storm, or great inundation from the river Kishon, took place at that time, which in poetic language was attributed to the stars. So our poet sung relative to the storms which dispersed the Spanish armada in 1588: -
"Both winds and waves at once conspire
To aid old England - frustrate Spain's desire."
Perhaps it means no more than this: the time which was measured and ruled by the heavenly bodies seemed only to exist for the destruction of the Canaanites. There may be also a reference to the sun and moon standing still in the days of Joshua.
God fought on the side of Israel, and gave them the victory. Josephus relates that, just as the battle began, a violent tempest came on with a great downfall of rain; and a hailstorm, which, driving full in the faces of the Canaanites, so blinded and benumbed them with cold, that they could neither use their bows with effect nor even hold their swords.