A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Chronicles 2:3
ch1 2:3POSTERITY OF JUDAH. (Ch1 2:3-12)
The sons of Judah--His descendants are enumerated first, because the right and privileges of the primogeniture had been transferred to him (Gen 49:8), and because from his tribe the Messiah was to spring.
1 Chronicles 2:6
ch1 2:6Zimri, and Ethan, and Heman, and Calcol, and Dara--These five are here stated to be the sons of Zerah, that is, of Ezra, whence they were called Ezrahites (Kg1 4:31). In that passage they are called "the sons of Mahol," which, however, is to be taken not as a proper name, but appellatively for "sons of music, dancing," &c. The traditional fame of their great sagacity and acquirements had descended to the time of Solomon and formed a standard of comparison for showing the superior wisdom of that monarch. Jewish writers say that they were looked up to as prophets by their countrymen during the abode in Egypt.
1 Chronicles 2:7
ch1 2:7the sons of Carmi--He was the son of Zimri, or Zabdi, as he is called (Jos 7:1).
Achar--or Achan (Jos 7:1). This variety in the form of the name is with great propriety used here, since Achar means "troubler."
1 Chronicles 2:15
ch1 2:15CHILDREN OF JESSE. (Ch1 2:13-17)
David the seventh--As it appears (Sa1 16:10; Sa1 17:12) that Jesse had eight sons, the presumption is from David being mentioned here as the seventh son of his father, that one of them had died at an early age, without leaving issue.
1 Chronicles 2:17
ch1 2:17Jether the Ishmaelite--(compare Sa2 17:25). In that passage he is called Ithra an Israelite; and there seems no reason why, in the early days of David, anyone should be specially distinguished as an Israelite. The presumption is in favor of the reading followed by the Septuagint, which calls him "Jetra the Jezreelite." The circumstance of his settling in another tribe, or of a woman marrying out of her own tribe, was sufficiently rare and singular to call for the statement that Abigail was married to a man of Jezreel.
1 Chronicles 2:18
ch1 2:18POSTERITY OF CALEB. (1Ch. 2:18-55)
Caleb the son of Hezron--The notices concerning this person appear confused in our version. In Ch1 2:19 he is said to be the father of Hur, whereas in Ch1 2:50 he is called "the son of Hur." The words in this latter passage have been transposed in the copying, and should be read thus, "Hur the son of Caleb."
begat children of Azubah his wife, and of Jerioth--The former was his spouse, while Jerioth seems to have been a secondary wife, and the mother of the children whose names are here given. On the death of his principal wife, he married Ephrath, and by her had Hur [Ch1 2:19].
1 Chronicles 2:21
ch1 2:21Hezron . . . daughter of Machir the father of Gilead--that is, chief of that town, which with the lands adjacent was no doubt the property of Machir, who was so desirous of a male heir. He was grandson of Joseph. The wife of Machir was of the tribe of Manasseh (Num 26:29).
1 Chronicles 2:22
ch1 2:22Jair, who had three and twenty cities in the land of Gilead--As the son of Segub and the grandson of Hezron, he was of the tribe of Judah; but from his maternal descent he is called (Num 32:41; Deu 3:14) "the son of Manasseh." This designation implies that his inheritance lay in that tribe in right of his grandmother; in other words, his maternal and adopting great-grandfather was Machir the son of Manasseh. Jair, inheriting his property, was his lineal representative; and accordingly this is expressly stated to be the case; for the village group of "Havoth-Jair" was awarded to him in that tribe, in consequence of his valiant and patriotic exploits. This arrangement, however, took place previous to the law (Num 36:1-13), by which it was enacted that heiresses were to marry in their own tribe. But this instance of Jair shows that in the case of a man obtaining an inheritance in another tribe it required him to become thoroughly incorporated with it as a representative of the family through which the inheritance was received. He had been adopted into Manasseh, and it would never have been imagined that he was other than "a son of Manasseh" naturally, had not this passage given information supplementary to that of the passage in Numbers.
1 Chronicles 2:23
ch1 2:23he took--rather "he had taken." This statement is accounting for his acquisition of so large a territory; he got it by right of conquest from the former possessors.
Kenath--This place, along with its group of surrounding villages, was gained by Nobah, one of Jair's officers sent by him to capture it (Num 32:1-2).
All these belonged to the sons of Machir--In their number Jair is included as having completely identified himself by his marriage and residence in Gilead with the tribe of Manasseh.
1 Chronicles 2:24
ch1 2:24Caleb-ephratah--so called from uniting the names of husband and wife (Ch1 2:19), and supposed to be the same as was afterwards called Beth-lehem-ephratah.
Ashur, the father of Tekoa-- (Sa2 14:2-4). He is called the father, either from his being the first founder, or perhaps the ruler, of the city.
1 Chronicles 2:34
ch1 2:34Sheshan had no sons, but daughters--either he had no sons alive at his death, or his family consisted wholly of daughters, of whom Ahlai (Ch1 2:31) was one, she being specially mentioned on account of the domestic relations about to be noted.
1 Chronicles 2:35
ch1 2:35Sheshan gave his daughter to Jarha his servant to wife--The adoption and marriage of a foreign slave in the family where he is serving, is far from being a rare or extraordinary occurrence in Eastern countries. It is thought, however, by some to have been a connection not sanctioned by the law of Moses [MICHAELIS]. But this is not a well-founded objection, as the history of the Jews furnishes not a few examples of foreign proselytes in the same manner obtaining an inheritance in Israel; and doubtless Jarha had previously embraced the Jewish faith in place of the grovelling idolatries of his native Egypt. In such a case, therefore, there could be no legal difficulty. Being a foreign slave, he had no inheritance in a different tribe to injure by this connection; while his marriage with Sheshan's daughter led to his adoption into the tribe of Judah, as well as his becoming heir of the family property.
1 Chronicles 2:42
ch1 2:42the sons of Caleb--(compare Ch1 2:18, Ch1 2:25). The sons here noticed were the fruit of his union with a third wife.
1 Chronicles 2:55
ch1 2:55the families of the scribes--either civil or ecclesiastical officers of the Kenite origin, who are here classed with the tribe of Judah, not as being descended from it, but as dwelling within its territory, and in a measure incorporated with its people.
Jabez--a place in Judah (Ch1 4:9).
Kenites that came of Hemath--who settled in Judah, and were thus distinguished from another division of the Kenite clan which dwelt in Manasseh (Jdg 4:11).