What does Judges 1:19 mean?

To this point, the book of Judges has followed Judah's campaign to defeat all the Canaanite peoples in their allotted territory. This verse summarizes their overall progress. It is a good news, bad news scenario. The good news is that because the Lord was with Judah, they were able to conquer the region known as the hill country in southern Israel. So far as Judah maintained faith in God, they could accomplish all He had asked them to do.

The bad news, though, is that they could not entirely drive out the inhabitants of the lowlands—meaning the plains—because those Canaanites had iron chariots. The use of iron in chariots was a relatively new technology at this moment in history, and Israel did not have a battle plan to overcome it on strictly human terms. Chariots could not help the Canaanites in the hilly regions of Judah, but they were very powerful on the plains.

The text makes no further comment about this difficulty. Readers are often confused, given that God's influence is supposed to be at work in these battles. The God that miraculously made Jericho's walls fall (Joshua 6:20–21) could also intervene to overcome iron chariots. The text does not say Judah was defeated, only that they didn't "drive out" those inhabitants. Later, Israel would successfully counter armies equipped with iron chariots (Judges 4). So why didn't God intervene here? Bible scholars are left to speculate, since the text offers no clues.

A common theme in Israel's failures in Canaan is complacency and lack of faith. It could be this limited victory was an early consequence of Judah's failure to utterly destroy some of the Canaanites they came across (Deuteronomy 20:16–18). It could also simply be that Judah's armies were fearful and apprehensive about fighting enemies with iron chariots. Whatever the reason, Judah failed to completely secure all their territory, though they were very successful overall.