“They captured it.” The conquest of Hebron is repeated in the Book of Judges, but in more detail. Here in Joshua is the overview history of the conquest of the Promised Land, while in Judges the emphasis is more on how the city was later ruled by judges and leaders (cp. Judg. 1:10-20). Hebron was a very important biblical city. Abraham and Sarah, Isaac and Rebecca, and Jacob and Leah are buried there, and it was where David was first acknowledged as king of Israel.
“the mouth of the sword.” Used to show great destruction, as if the sword was eating its victims (see commentary on Josh. 6:21).