1)
What does the verse teach about these people?
1.
Radak: All of them were Nesi'im of families of Shevet Shimon and Roshei Batei Avos. They went to seek another inheritance after David became king. The land used to belong to Bnei Cham. They eradicated them until today, and dwelled in place of them.
2.
Malbim: There were 13 cities of Shimon (excluding the Chatzeros), and 13 family heads called on their names. Each family had a particular head. These names were in the days of Chizkiyah; the episode below (39) was in his days.
