The ESV Study Bible writes “The military encounters here are reminders that the peace at the end of the book of Joshua was short-lived. Judah was given a leadership role, and they allied with Simeon against the remaining Canaanites. They had some successes, but some ominous failures as well (vv. 19, 21).”
The secular character of this first chapter is setting the stage for what will be a failed mission. You have to do God’s work in God’s way.
LORD, give us the courage to attack the task you give us with wholehearted devotion.
Judges 1