John Gill Commentary Judges 1:9

"And afterward the children of Judah went down to fight against the Canaanites that dwelt in the hill-country, and in the South, and in the lowland." — Judges 1:9 (ASV)

And afterwards the children of Judah
After the taking of Bezek, and the king of it, having him to Jerusalem, where he died: they

went down ;
from Jerusalem; which was on high ground:

to fight against the Canaanites that dwelt in the mountain, and in the
south, and in the valley ;
into which several parts the lot of the tribe of Judah was divided; in each of which they had cities, and some, as it seems, yet unsubdued, and in the hands of the Canaanites; of these several parts, and the cities in them, see (Joshua 15:21Joshua 15:33Joshua 15:48) .