John Gill Bible Commentary

And Othniel the son of Kenaz, the brother of Caleb, took it,.... The relation of Othniel to Caleb is a little intricate, and, as it is understood, occasions objections to the marriage of Caleb's daughter to him; it seems, at first sight, that he was Caleb's own brother, a younger brother, and so uncle to his daughter, and such marriages were forbidden, Lev 18:14. Jarchi thinks he was the brother of Caleb by his mother's side; Kimchi, both by father and mother's side; but not to observe, that besides the word "brother" sometimes signifies only a kinsman, or near relation, and not precisely a brother; it is not Othniel that is called the brother of Caleb, but Kenaz, who was the father of Othniel; so that Caleb was Othniel's uncle, and Achsah and Othniel were brothers' children, or first cousins, between whom marriage was allowed of: and he gave him Achsah his daughter to wife; according to the tenor of his proclamation, and the promise he made.