Jamieson, Fausset and Brown on 1 Chronicles 2:18

18. Caleb the son of Hezron--The notices concerning this person appear confused in our version. In 1Ch 2:19 he is said to be the father of Hur, whereas in 1Ch 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 [1Ch 2:19].