Everyone in Judah was there--little children, wives, sons--all present and attentive to God. (2 Chronicles 20:11.)
Jehoshaphat and Judah were under attack from neighboring countries, and the king called for a national day of prayer. One might expect men of fighting age to show up. "Everyone was there." The writer felt compelled to clarify whom he meant by "everyone." Little children, wives, sons--the majority of the people of Judah came to Jerusalem for the occasion.
Two verses later, Jahaziah gave the multitude God's answer: "Attention EVERYONE. . .God's word:
This is God's war, not yours. . ."
It's not surprising that the men brought their families for worship. What is jaw-dropping odd to me is that they brought them to war.
The next morning, they left for the battlefield (after a rousing worship service, complete with choir and orchestra). It doesn't say only the men followed the king. Perhaps the same "everyone" came along. After all, the prophet had promised, "You won't have to lift a hand in this battle." and God had commanded, "March out boldly." What could be bolder than bringing along entire families as if this was a picnic?
Of course, our 20-20 hindsight tells us that God set the armies to fighting each other instead of Judah and they all died. It took the Judeans three days to clear the loot. Maybe they needed all the hands to carry the extra!
There are times that God calls us to act as a single body. Each body part has a different role to play, but all are needed. Even the women and children. :)
Not to mention they started with prayer, music, and preaching. Hey, that sounds like church! We enter to worship together and leave for the battle . . .