What does Judges 1:6 mean?

The leader or governor of the city of Bezek was apparently known by the title Adoni-Bezek, which simply means "master of Bezek." This enemy ruler fled after his city was defeated by the soldiers of the tribe of Judah (Judges 1:4–5). The soldiers chase down the Adoni-bezek, and eventually capture him. What the men of Judah do next is troubling, at best: they cut off the man's thumbs and his big toes. This mutilation emphasizes the ruler's weakness and utter defeat.

And so, in their first military action after the death of Joshua, Israel has already begun to imitate the wicked people of Canaan (Deuteronomy 7:1–5; 9:4). As the prisoner himself reveals in the following verse, this style of mutilation, used against a captured leader, was a common Canaanite practice (Judges 1:7). The Israelites were following the brutal, local customs. According to this passage, the defeated ruler might have been kept as a trophy, of sorts, until his own death.

What the soldiers of Judah should have done, according to the commands of the Lord, was to execute the enemy leader, not maim him. God had been extremely clear on that point (Deuteronomy 20:16–17). While this, itself, also seems harsh, there was good reason for it. Primarily, God wanted Israel to avoid taking on any aspects of Canaanite culture: "…that they may not teach you to do according to all their abominable practices that they have done for their gods, and so you sin against the Lord your God" (Deuteronomy 20:18).

This incident, as with many others to come, records Israel's refusal to fully destroy the depraved people of Canaan. This will eventually lead them to worship foreign gods, breaking their covenant with the Lord. Though it might seem a minor incident, this torture of a captured leader begins that pattern of disobedience.