Commentary for Judges 5:8

When they chose new gods—there was war in the cities. When the Yisroelites preferred modern Deities, then they needed to engage in battle in their cities. But, take note, now, when they volunteered, was a shield or battle ax in sight among the Yisroelites when they needed to do battle with the forty thousand field marshals the idolators flung against them? The Omnipresent overwhelmed them all with celestial warfare, and the Kishon stream swept them away.

They chose new gods: For when Israel chooses new gods, then war comes to their cities on account of the punishment; but not when they better their ways. As was it not that in the days of Yehoshua, it was stated (Joshua 4:13), "About forty thousand, etc. went across, etc. to the steppes of Yericho?" And was there any shield and spear seen with these forty thousand? For was it not by a miracle that they captured Yericho, and not through war and with a shield and a spear?

from the language of war