Albert Barnes Commentary Joshua 19:47

"And the border of the children of Dan went out beyond them; for the children of Dan went up and fought against Leshem, and took it, and smote it with the edge of the sword, and possessed it, and dwelt therein, and called Leshem, Dan, after the name of Dan their father." — Joshua 19:47 (ASV)

The words “too little” are an insertion of the King James Version; render it instead as: “the border of the children of Dan was extended.” The Hebrew appears to mean, “the children of Dan enlarged their border because they did not have enough room.”

The reason for this was that the Danites, a numerous tribe (Numbers 26:5 note), found themselves (Judges 1:34–35) cooped up among the hills by the powerful and warlike Amorites. Hence, the Danite expedition (see the marginal reference), which surprised the Sidonian inhabitants of Leshem, an unwarlike and peaceable race, exterminated them and annexed their city and territory to the portion of Dan.