John Wesley on Joshua 15:16

To wife - Which is to be understood with some conditions, as, if he were one who could marry her by God's law; and if she were willing; for though parents had a great power over their children, they could not force them to marry any person against their own wills. He might otherwise be an unfit and unworthy person; but this was a divine impulse, that Othniel's valour might be more manifest, and so the way prepared for his future government of the people, Judg 3:9.