Charles Ellicott Commentary 1 Chronicles 2:22

"And Segub begat Jair, who had three and twenty cities in the land of Gilead." — 1 Chronicles 2:22 (ASV)

And Segub begat Jair ... — The Havothjair (tent-villages of Jair) are mentioned several times in the Pentateuch. In Numbers 32:39-42, it is related that:

1. the Manassite clan of the sons of Machir took Gilead from the Amorites;
2. Moses then formally assigned Gilead “to Machir son of Manasseh,” and the clan accordingly settled there; and
3. Jair son of Manasseh had taken their (i.e., the Amorite) tent-villages, and called them Havoth-jair.

Compare to Deuteronomy 3:14-15: Jair son of Manasseh had taken all the region of Argob to the borders of the Geshurite and the Maacathite; and he called them (that is, Bashan) after his own name, Havoth-jair, to this day. And to Machir I gave Gilead.

1 Chronicles 2:21–23 show a connection between Jair and the two tribes of Judah and Manasseh. This connection is established as follows:

Hezron, a descendant of Judah through Pharez, married the daughter of Machir. Machir was the chief of Gilead and from the tribe of Manasseh. The son of Hezron and Machir’s daughter was Segub, and Segub, in turn, fathered Jair. Therefore, Jair possessed lineage from both Judah and Manasseh.

Jair is, of course, the name of a group of kindred families or clans, settled in the twenty-three cities.