Charles Ellicott Commentary Judges 20:34

"And there came over against Gibeah ten thousand chosen men out of all Israel, and the battle was sore; but they knew not that evil was close upon them." — Judges 20:34 (ASV)

Ten thousand chosen men. — Though the verse is obscurely expressed, the meaning probably is that this was the number of the ambush of picked warriors. If it means that this was the Israelite force left after the slaughter of 40,000, we are not told the number of the ambush.

The battle was sore. — This would describe a battle in which the Benjamites were now attacked both from the front and the rear.

But. — Rather, and.

They knew not that evil was near them — i.e., in other words, “that the hour of their ruin had come,” or, as the Vulgate puts it, quod ex omni parte illis instaret interitus, “that destruction was threatening them on every side.” (Compare to Isaiah 47:10.)