Caleb: This was not Caleb the son of Jephunneh, but Caleb the son of Hezron, and therefore called the brother of Jerahmeel. See the parallel texts. 1 Chronicles 2:9, Chelubai, 1 Chronicles 2:18-19, 1 Chronicles 2:24
his firstborn: Genesis 49:3; Exodus 4:22-23; Romans 8:29; Hebrews 12:23
the father: i.e. the founder, Or, as the Targum renders, "the prince of the Ziphites;" for it was usual to call both the founder and the prince of a city its father.
Ziph: Joshua 15:24; 1 Samuel 23:19, 1 Samuel 26:1
the father of Hebron: 1 Chronicles 2:23-24, 1 Chronicles 2:45, 1 Chronicles 2:49, 1 Chronicles 2:52, 1 Chronicles 8:29; Ezra 2:21-35; Nehemiah 7:25-38